Book - Buchanan's Manual of Anatomy including Embryology 7
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Frazer JE. Buchanan's Manual of Anatomy, including Embryology. (1937) 6th Edition. Bailliere, Tindall And Cox, London.
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- 1 Chapter VII The Bones Of The Lower Limb
Chapter VII The Bones Of The Lower Limb
The lower limb is arranged in four divisions—namely, hip or pelvic girdle, thigh, leg, and foot. The pelvic girdle consists of the hip bone; the thigh comprises the femur, with which is associated the patella; the leg is composed of the tibia and fibula; and the foot is subdivided into a tarsus, consisting of seven bones, a metatarsus, comprising five bones, and phalanges, which are fourteen in number.
The Hip Bone or Innominate Bone
The hip bone (os coxae) forms the lateral, and one half of the anterior, wall of the pelvis. It is much twisted, quadrilateral, and constricted about the centre. The lateral surface is characterized by the acetabulum, and below and medial to this is the obturator foramen. In early life the bone is composed of three parts—ilium, ischium, and pubis—which unite in the acetabulum, and in the adult it is described under these three divisions.
The ilium is the expanded portion above the acetabulum, of which it forms rather less than the upper two-fifths. It presents three borders and two surfaces.
The superior border or crest is thick over its anterior and posterior thirds, but thin over the middle third. It presents two curves— anterior with the concavity directed inwards, and posterior with the concavity outwards. Anteriorly it terminates in the anterior superior spine, which gives attachment to the inguinal ligament and a portion of the sartorius. Posteriorly it ends in the posterior superior spine, which gives attachment to the long posterior sacro-iliac ligament. The crest has two lips and an intervening space. The outer lip presents a tubercular prominence about 3 inches from the anterior superior spine. Over its whole extent this lip gives attachment to the fascia lata; for ij inches in front, to the tensor fasciae latae; over its anterior half to the obliquus externus abdominis; and a little behind this, to r* 5 ^^ssimus dorsi. The intervening space over its anterior twothirds gives origin to the obliquus internus abdominis, and over its posterior fifth to the sacro-spinalis. The inner lip over its anterior wo-tmrds gives origin to the transversus abdominis, and for about 2 inches posteriorly to the ilio-lumbar ligament and quadratus lumorum. Immediately within the inner lip, over its anterior two-thirds, ie tasaa transversalis and fascia iliaca take attachment.
ie anterior border extends from the anterior superior spine to the ilio-pubic eminence. Superiorly it presents the anterior interspinous notch, the upper part of which gives partial origin to the sartorius. Below this notch is the anterior inferior spine, which gives origin anteriorly to the straight head of the rectus femoris, and interiorly to the ilio-femoral ligament. Medial to this spine there is a groove for the passage of the ilio-psoas, and medial to the groove is the iliopubic eminence, which marks the junction of the ilium and superior pubic ramus. This eminence gives attachment to the ilio-pectineal intermuscular septum, and, it may be, partial insertion to the psoas minor.
Fig. 213. —The Right Hip Bone (Lateral Aspect).
The posterior border extends from the posterior superior spine to a point a little below the deepest part of the greater sciatic notch, where there is usually a faint transverse line on the lateral surface, indicating the place of junction of the ilium and ischium. Superiorly it presents the posterior interspinous notch, and below this the posterior inferior spine, which gives attachment to the sacro-tuberous ligament, whi' immediately below this it gives origin to fibres of the pyriform Inferiorly the posterior border forms the upper part of the great sciatic notch, over which the pyriformis passes as it leaves the pelvi The gluteal surface or dorsum ilii, concavo-convex from behii forwards, is traversed by three ridges, called the posterior, midd' and inferior gluteal, or curved, lines. The posterior gluteal line coi mences at the outer lip of the crest about 2 inches in front of t] posterior superior spine, and passes downwards to the upper part the greater sciatic notch. The semilunar area of gluteal surface abo’ and behind this line gives origin to the gluteus maximus. The mida gluteal line starts at the outer lip of the crest ij inches behind t] anterior superior spine, and passes backwards and downwards to t] upper part of the greater sciatic notch, where it terminates close to tl superior line. The surface included between the middle gluteal lin crest, and posterior gluteal line, which is falciform, gives origin to tl gluteus medius. The inferior gluteal line begins at the lower part of tl anterior interspinous notch, whence it passes backwards to the deepe part of the greater sciatic notch. The space between the inferi< and middle gluteal lines gives origin to the gluteus minimus. Betwee the front part of the inferior gluteal line and the margin of the acetabi lum there is a short transverse roughness, which gives origin to tt reflected head of the rectus femoris. The iliac portion of the bone very thin and translucent toward the upper part of the middle thin where it is sometimes perforated, and it presents a strong rounde ridge, leading upwards from the margin of the acetabulum to th tubercular eminence on the outer lip of the crest. There is also strong bar of bone extending from the upper margin of the acetabulur to the auricular surface on the medial aspect.
the sacro-pelvic surface is divisible into an anterior and a posteric portion. The anterior division, which occupies two-thirds, is sut divided into a small lower and large upper part by the iliac portio of the arcuate line, the direction of which is forwards and downward: 1 he part below and behind the line enters into the lateral wall of th true pelvis, and gives origin to a portion of the obturator internu: Ihe part above the line is extensive and concave, and forms the ilia fossa, which lodges the iliacus muscle. The iliac portion of the arcuat line gives attachment to the iliac fascia. It may also give partk insertion to the psoas minor near the ilio-pubic eminence. The posteric division is subdivided into auricular, ligamentous, and muscular poi tions. The auricular area, antero-inferior in position, is broad in fron and narrow behind, where it extends over the inner aspect of th posterior inferior spine. It is covered by cartilage in the recent state and articulates with the auricular surface of the sacrum. The liga mentous area, situated above and behind the auricular, is rough an( tubercular for the posterior sacro-iliac ligament. The muscular area placed superiorly, gives origin to fibres of the multifidus. Below tfi auricular facet the auricular groove ’ is seen in the female, but not in the male; sometimes it extends behind and sometimes in front of the surface as well. It is formed by ligaments, and is a very valuable sexual distinction of the hip bone.
The ischium forms the lower and back part of the bone, and is livisible into a body, tuberosity, and ramus. The body contributes ather more than two-fifths to the acetabulum, and forms the greater >ortion of its non-articular part. It is prismatic, and its surfaces are medial, lateral, and posterior. The medial surface extends from near he centre of the arcuate line to the ischial spine, and is narrow above, >ut widens interiorly before reaching the spine. Its place of junction yith the ilium is indicated by a line passing from the ilio-pubic eminence >ackwards and downwards to a point a little below the deepest part of the greater sciatic notch. Its junction with the superior pubic amus is marked by a line passing from the ilio-pubic eminence downwards to the posterior margin of the obturator foramen about f in< below its upper end. This surface gives origin to part of the obturat internus. The lateral surface enters into the acetabulum, and betwe( that cavity and the tuberosity it presents an obturator groove f< the tendon of the obturator externus. The upper part of this groo^ gives attachment to the ischio-femoral ligament. The posterior surf a is limited laterally by the brim of the acetabulum, behind by tl posterior border, and below by the upper border, of the tuberosit; At the lower part is a portion of the obturator groove, and it suppor the pyriformis, and the sciatic nerves and vessels.
Fig. 214. — The Right Hip Bone (Medial Aspect).
The borders are anterior, lateral, and medial. The anterior bord< forms a portion of the posterior margin of the obturator foramen, ar is sharp. It separates the medial from the lateral surface. The later border forms the posterior part of the margin of the acetabulum, an gives attachment to a part of the labrum acetabulare. The medi < border is continuous with that of the ilium. Superiorly it forms tt lower part of the greater sciatic notch, below which it presents a pr< jection, called the spine, which has an inward curve towards the pelvi and gives attachment to the following structures: the sacro-spinoi ligament at the tip, the levator ani, coccygeus, and white line of tt pelvic fascia on the inner surface, and the gemellus superior along tl lower border. The lateral surface (back) supports, from within ou wards, the pudendal nerve, internal pudendal vessels, and nerve to tt obturator internus. Below the spine is the lesser sciatic notch, whic is covered by cartilage, and is ridged in the recent state for the play ( the tendon of the obturator internus.
Ihe tuberosity (tuber ischii) forms the thick dependent part, an supports the body in the sitting posture. The upper border limil interiorly the obturator groove and lesser sciatic notch, and in tb latter situation it gives origin to the gemellus inferior. The innt border is prominent and sharp, and gives attachment to the sacrc tuberous ligament. The outer border gives origin to the quadratr femoris. The anterior border is sharp and prominent, and forms tb lower part of the posterior margin of the obturator foramen. Tb surfaces are posterior, lateral, and medial. The posterior surface lie between the outer and inner borders, and is somewhat quadrilatera and is subdivided into two parts by a diagonal line directed downward: forwards, and outwards. The upper and outer part gives origin t the semimembranosus, and the lower and inner to the conjoined Ion head of the biceps and semitendinosus. The inferior surface, whic is in line with the inner margin of the ramus, is rough and triangulai and gives origin to fibres of the adductor magnus. The lateral surfac is situated between the outer and anterior borders, and supports th obturator externus. The internal surface is placed between the inne and anterior borders. It looks towards the ischio-rectal fossa, an gives origin to fibres of the obturator internus.
Ihe ramus is the compressed portion which extends upwards an inwards from the tuberosity on the inferior aspect of the obturator foramen, where it joins the inferior pubic ramus, the place of meeting being indicated laterally by a rough ridge. The upper border is sharp, and forms part of the margin of the obturator foramen. The lower border is thick, and anteriorly it is rough for the attachment of the deep layer of superficial perineal fascia, crus penis, and ischio-cavernosus muscle. In the female this part gives attachment to the crus clitoridis. The outer surface gives origin, from within outwards, to portions of the adductor magnus and obturator externus. The inner or pelvic surface gives attachment to part of the obturator internus and parietal pelvic fascia. At its lower part, near the inner border, there is a sharp ridge which gives attachment to the falciform process of the sacro-tuberous ligament.
The os pubis lies in the anterior wall of the pelvis, and is composed of a body and two rami, superior and inferior. The body is compressed from before backwards, and occupies an oblique plane, which is directed downwards and backwards. It presents three surfaces—anterior, posterior, and medial. The anterior or femoral surface has an inclination downwards. At its upper and inner part, below and lateral to the pubic angle, it gives origin to the adductor longus, and, lower down, to the following muscles, in order from within outwards: gracilis, adductor brevis, a small portion of the adductor magnus, and obturator externus. The posterior or pelvic surface has an inclination upwards, and gives attachment from without inwards to the obturator internus, parietal pelvic fascia, levator ani, and pubo-prostatic ligament. Much of the pelvic fascia, in the undissected state, is loose cellular tissue, which, in this region, forms the ‘ cave of Retzius/ The medial surface is oval, with its long axis directed downwards and backwards. It is covered by hyaline cartilage, and articulates with its fellow to form the symphysis pubis, a plate of fibro-cartilage intervening.
The borders are lateral and superior. The lateral border , which is sharp, looks into the obturator foramen, and gives attachment to part of the obturator membrane. The superior border or crest is thick, and about an inch long. At its outer extremity is the pubic tubercle , which may be blunt or sharp, for the attachment of the inguinal ligament, and medially is the pubic angle , which surmounts the medial surface. The crest gives attachment to the conjoint tendon, pyratnidalis, and outer head of the rectus abdominis.
The inferior ramus passes downwards, backwards, and outwards, md corresponds in all respects with the ischial ramus, which it joins, its anterior surface gives origin, from within outwards, to the adductor brevis, adductor magnus, and obturator externus. The structures ittached to the posterior surface are portions of the obturator internus, sphincter urethrae, and parietal pelvic fascia. The lower border, which orms the subpubic arch, with its fellow of the opposite side, attaches he gracilis laterally, and the pull of this muscle everts the border in >oth sexes.
The superior ramus extends outwards and upwards from the body to the ilio-pubic eminence and anterior part of the acetabulum, of whicl latter it forms one-fifth. It lies above the obturator foramen, and 1 prismatic. Superiorly, at the back part, is a prominent ridge, repre senting the pectineal portion of the arcuate line, which leads to th< pubic tubercle, and gives attachment to the following structures: thi pubic lamina of the fascia lata, pectineus, pectineal part of inguina ligament, and conjoint tendon. In front of this line is the superio ; or pectineal surface, which is sloped downwards and forwards, and i: triangular. It attaches the pectineus, and is limited antero-inferiorl} by the obturator crest, which extends from the pubic tubercle to th< anterior margin of the acetabular notch. The inferior surface present; the obturator groove for the obturator vessels and nerve, the direction o; which is downwards, forwards, and inwards. The posterior surface gives partial origin to the obturator internus.
The acetabulum or cotyloid cavity is situated on the outer surface of the bone, and is directed downwards, outwards, and forwards. Ii is a deep, circular concavity, and articulates with the head of the femur. The ischium forms rather more than two-fifths of it, the iliurr rather less, and the os pubis the remaining fifth. It is surmounted bj a prominent brim, upon which the labrum acetabulare is set, excepl at the anterior and inferior part, where there is the acetabular notch this being bridged oyer by the labrum and transverse ligaments. The capsular ligament is attached to the bone just outside the brim The interior is divided into two parts—articular and non-articular lhe articular portion is covered by cartilage, which is arranged in the form of a horseshoe, and surrounds the circumference, except opposite the acetabular notch, lhe non-articular part, which is formed mainl) by the ischium, is depressed, and lodges the Haversian pad of fat.
The obturator or thyroid foramen lies below, and medial to, the acetabulum, its boundaries being formed by the ischium and pubis, Its long diameter is directed downwards and outwards, but is much more vertical in the male than in the female. Its circumference is sharp for the obturator membrane, which closes the opening, except opposite the obturator groove superiorly, where it converts that groove into the obturator canal.
The greater and lesser sciatic notches are situated on the posterior f k° ne > an d are separated from each other by the spine of the ischium, Hie greater notch is formed partly by the ilium, and partly by the ischium; and the lesser notch lies between the ischial spine and tuberosity.
In the recent state these notches are converted into foramina by the sacro-tuberous and sacro-spinous ligaments. For the structures
which pass through these foramina, see the description of the gluteal region.
The hip bone is pierced by a great number of nutrient foramina for arteries, the chief of which are situated as follows: along the inner aspec o ie crest for branches of the deep circumflex iliac; in the iliac ossa near e auncular surface, where there are one or two for branches of the ilio-lumbar; on the lateral surface of the ilium and around the margin of the acetabulum for branches of the gluteal; between the acetabulum and ischial tuberosity for branches of the obturator; on the ilio-pectineal eminence for branches of the deep circumflex iliac;
Appears about the 8th Week (intra-uterine)
Appears about the 5th Month (intrauterine)
Appears about the 3rd Month (intrauterine)
Fig. 215.—Ossification of the Hip Bone.
and over the body of the os pubis for branches of the obturator, and of the pudendal branches of the femoral.
Articulations. — Posteriorly with the sacrum, laterally with the femur, and medially with its fellow.
Ossification. — The hip bone is ossified in cartilage from three primary and nine secondary centres. The primary centres are iliac, ischial, and pubic. The iliac centre appears in the eighth week; the ischial centre in the third month’, and the pubic centre in the fifth month in the superior pubic ramus.
Appears about the 15th Year, and joins about 25
Appears about the 15th Year,_
and joins about 25
Represents the Os Acetabuli
Appears about the 15th Year, and joins about 25
-Appear about the 12th Year,
lll/£^\ and join about 18
Appears about the 15th Year, and joins about 25
Appears about the 15th Year, and joins about 25
Join in the 8th Year
Fig. 216. — Ossification of the Epiphyses of the Hip Bone.
The ischial and inferior pubic rami join about the seventh year (M.) or fifth year (F.).
The ilium and ischium join about puberty.
Acetabulum. — The superior pubic ramus is shut out from this cavity for some time by a triangular portion of cartilage, called the pars acetabularis. From its apex there is prolonged backwards a strip of cartilage ( ilio-ischial ).
The entire cartilage resembles the letter Y laid on its side. The open par of the Y is directed forwards, and forms the pars acetabularis. The Y cartilag< has three secondary centres. One, called the acetabular centre, appears in th< twelfth year in the pars acetabularis, and ossification is completed by th e fourteenth year. It then forms a distinct bone, called the OS acetabuli, which joins th< superior pubic ramus about the sixteenth year.
The other two secondary centres for the Y cartilage appear about the fourteent} year, one of them in the ilio-ischial strip or stem of the Y; and the other ai the meeting of the two limbs and stem of the Y. The ossification of the bottorr of the acetabulum is completed from the sixteenth to the eighteenth year.
Other Secondary Centres. —These are as follows: (i) One, or more often two for the crest, one for the anterior inferior iliac spine, one (a thin scale) for the surface of the ischial tuberosity, each of these centres appearing about the fifteenth year ; (2) one for the pubic tubercle, and one for the pubic angle, each of these two centres appearing about the eighteenth year. These epiphyses usually joir about the twenty-first year. For medico-legal purposes it is most important tc realize that the times of appearance and junction of these secondary centres are mos , variable, and that, as a rule, they are earlier in females than in males.
The centre for the anterior inferior spine is interesting in that it only occurs in man; and in man alone do we find a straight head to the rectus femoris. II will be seen, therefore, that the sequence of events is (1) the assumption of the erect position; (2) the necessity of a straight head for the rectus; (3) a tractior epiphysis, due to the pull of the newly formed straight head. The spines of the ischium and pubes may be epiphyses or apophyses; in any case they are practically human structures, and their appearance is probably due to tractior coming into play in the upright position.
The epiphysis on the tuberosity of the ischium is atavistic, and marks the remains of the hypo-ischium or os cloacae of reptiles, while that at the angle of the pubes is the remnant of the prepubis of amphibians.
The pelvis is formed by the hip bones, sacrum, and coccyx, the hip bones constructing the anterior and lateral walls, whilst the sacrum and coccyx lie in the posterior wall. It is divided into two parts, called false pelvis and true pelvis, the division being effected by a plane passing through the upper border of the symphysis pubis, arcuate line, and sacral promontory.
The false pelvis, which lies above this plane, is formed by the iliac fossae, and constitutes a part of the abdomen proper.
The true pelvis is situated below the plane referred to, and presents a brim or inlet, a cavity, and an outlet. The brim is formed in front by the upper border of the symphysis pubis, behind by the sacral promontory, and between these two points by the following parts from before backwards: the angle and crest of the pubis, the arcuate line, and the antero-inferior border of the ala of the sacrum. In the male it is cordate, the base of the heart, which is encroached upon by the sacral promontory, being directed backwards. In the female it is oval, the long diameter being transverse. The diameters of the brim are antero-posterior or conjugate, transverse, right oblique, and left oblique I he antero-posterior or conjugate diameter extends from the uppei border of the symphysis pubis to the sacral promontory; the transverse rom one arcuate line to the opposite, across the widest part of the brim; and the oblique, from one sacro-iliac articulation to the iliopubic eminence of the opposite side. The oblique diameters are called right and left from the sacro-iliac articulations whence they extend.
Fig. 217. — The Male Pelvis.
Fig. 218. — The Female Pelvis.
The cavity is bounded in front by the bodies and rami of the pubic bones, behind by the sacrum and coccyx, and laterally by an extensive osseous plane, formed chiefly by the pelvic surface of the ischium, but also by that of the ilium, and terminating below in the incurved ischial spine. It is shallow in front, where its depth is from i\ to 2 inches but deep behind, where it measures about 5J inches, following th curve of the sacrum. The plane of the anterior wall is oblique, bein ; directed downwards and backwards. The posterior wall is curved and at its upper part looks mainly downwards. The antero-posterio diameter of the cavity extends from the centre of the symphysis pubi to the upper margin of the third sacral segment; the transverse , from point corresponding to the lower margin of the acetabulum on ou side to the corresponding point on the other; and the oblique, from th< centre of the greater sciatic foramen on one side to the centre of th< obturator membrane on the other.
The outlet presents three prominences—namely, the ischial tuber osity at either side, and the tip of the coccyx in the median line pos teriorly. Its boundaries, at either side from before backwards, ar as follows: the lower border of the symphysis pubis, inferior ramus 0 the pubis, ramus of ischium, ischial tuberosity, sacro-tuberous ligamen in the recent state, and tip of the coccyx. In front of an imaginary line connecting the ischial tuberosities is the subpubic arch, which i: bounded at either side by the ischio-pubic ramus and above by thei: meeting to form the subpubic angle. The arch is occupied by the perineal membrane, the plane of which slopes downwards and back wards. The antero-posterior diameter of the outlet extends from th< lower border of the symphysis pubis to the tip of the coccyx; the trans verse, from one ischial tuberosity to the other; and the oblique, fron the middle of the lower border of the sacro-tuberous ligament on on( side to the place of union between the inferior pubic and ischial ram on the other.
The Inclination of the Pelvis. —In the erect posture the plane of thf pelvic brim forms with the horizontal an angle of from 50 to 60 degrees and the base of the sacrum is about 3! inches above the upper bordei of the symphysis pubis. The brim, therefore, is disposed obliquely sloping upwards and backwards. An idea of this obliquity may be obtained by placing a pelvis against a wall in such a way that the sacroiliac joint is directly above the acetabulum. A line connecting the tip of the coccyx with the lower border of the symphysis pubis forms with the horizontal an angle of about 11 degrees, and the tip of the coccyx is about f inch above the subpubic angle. The direction of the p ane of the outlet slopes downwards and backwards, principally c ownwards. The plane of the symphysis pubis forms with the horizontal an angle of from 35 to 40 degrees. It is worthy of note that the sacro-vertebral angle is estimated at 117 degrees in the male, and as much as 130 m the female.
The Axes of the Pelvis. — The axes represent imaginary lines intersec ing e planes of the brim, cavity, and outlet at right angles through eir C( r n t 1£ d points. The axis of the brim corresponds with a line rawn rom the umbilicus to the sacro-coccygeal articulation, and its direction is downwards and distinctly backwards. The axis of the
e represents a line drawn from the sacral promontory through the centre of the outlet, and its direction is downwards and very slightly backwards. The axis of the cavity intersects planes having different inclinations, and is necessarily curved, the concavity being directed forwards. It is described as ‘ the perpendicular of a line drawn from the middle of the symphysis pubis to the centre of the sacro-coccygeal curve.' The average measurements of the axes of the female pelvis are as follows:
Sexual Differences.—The differences in the two sexes are as follows:
Bones smoother and more slender.
Acetabula wide apart.
True pelvis wider and shallower.
Obturator foramen triangular.
Ischial tuberosities wider apart and everted.
Span of subpubic arch wide.
Lower border of ischio-pubic ramus comparatively smooth and thin.
Brim transversely oval.
False pelvis narrower.
Sacral promontory less projecting.
Sacrum broader, shorter, and straighter.
Coccyx more movably articulated with sacrum.
Symphysis pubis shallower.
Acetabulum less than 5 cm. in diameter.
Auricular groove present.
Ischial spine not very projecting.
Body of pubis quadrilateral.
Bones rougher and more massive.
Acetabula not so wide apart.
True pelvis narrower and deeper.
Obturator foramen oval.
Ischial tuberosities not so wide apart and inverted.
Span of subpubic arch narrow.
Lower border of ischio-pubic ramus strongly marked and thick.
False pelvis wider.
Sacral promontory more projecting.
Sacrum narrower, longer, and more curved.
Coccyx less movably articulated with sacrum.
Symphysis pubis deeper.
Acetabulum more than 5 cm. in diameter.
Auricular groove absent.
Ischial spine projecting markedly into pelvic cavity.
Body of pubis triangular.
The Pelvis of the Child.—The pelvis is of small size in the child. The iliac alae are expanded, and the cavity is of small dimensions; a large part of the urinary bladder in both sexes, therefore, lies in the hypogastric region of the abdomen. The sacro-vertebral angle is relatively greater, and the pelvis has consequently a greater inclination.
The femur extends from the hip to the knee, its direction being downwards, inwards, and slightly backwards. It is a long bone, and is divisible into a shaft and two extremities, upper and lower.
The upper extremity consists of a head, neck, and two trochanters. The head forms rather more than half a sphere, and is covered by
The position of the coccyx makes this variable.
articular cartilage except at a point a little below and behind its centre, where a rough depression, known as the pit for ligament of head of femur. Roughly speaking, a head which is more than 45 mm. in diameter is that of a male, less than 45 mm., of a female. For medicolegal purposes 46 mm. and over is almost certainly male, while 42 mm. and below is almost equally certainly female. This, of course, applies to adult English bones.
The neck is directed inwards, upwards, and backwards; it averages about 65 mm. in length in males, and 56 mm. in females, and the angle which it makes with the shaft is 126 degrees, though the range of variation may be anything from 113 to 140 degrees. Generally speaking, long femurs have the most vertical necks, though in old age the angle diminishes and the neck appears shorter.
When viewed from in front or behind the neck appears pyramidal with the base towards the shaft, but when looked at from above or below the pyramid has the base towards the head.
Where the neck joins the shaft, in front, is a rough line which may be traced down in front of the lesser trochanter to the'back of the shaft; it is known as the trochanteric line, and attaches the capsule of the hip-joint.
At its upper end, and also opposite the lesser trochanter, are two specially rough markings, called the upper and lower tubercles of the neck, which attach the two limbs of the ilio-femoral or Y-shaped ligament of the hip.
The trochanteric line was formerly called the spiral line, which is
probably a better name, since the line passes well in front of the lesser trochanter.
In front of the neck, close to the head, there is usually a rough, 11 regular area, which may be caused by the pressure of the margin of the acetabulum in extreme flexure of the hip.
It will be seen from the above description that the whole of the front of the neck is intracapsular.
Posteriorly the neck is only intracapsular in its inner two-thirds, the outer third being smooth for about a finger’s breadth where the obturator externus muscle plays over it, and, at the junction of the mtra- and extra-capsular parts, the posterior portion of the capsule is practically non-adherent.
The intracapsular part of the neck has many foramina, and is longitudinally ridged for the retinacula of the hip-joint.
The greater trochanter is a lever, for the attachment of muscles, projecting directly upwards from the shaft. Perhaps the most convenient way of studying it is to regard it as cuboidal and to look at it consecutively from six points of view.
Anteriorly is a triangular surface for the attachment of the gluteus minimus laterally and for a bursa medially.
Posteriorly the bone shows little more than a rounded border, which,
w lere 1 joins the shaft, is heaped up into an eminence known as the quadrate tubercle.
Fig. 219.—The Right Femur (Anterior View).
Laterally is a quadrilateral surface bisected by the diagonal lin which runs from the postero-superior to the antero-inferior angle, an< attaches the gluteus medius. Above this line is a bursa.
Medially the surface is only free posteriorly where it is hollowed ou to form the digital or trochanteric fossa for the attachment of thi obturator externus tendon and, in front of this, the obturator internu: and gemelli.
Superiorly the trochanter is little more than a border, to the greatei part of which the pyriformis is attached. It may be useful here tc notice that, when the femur is in position, a line drawn horizontall} inwards from the top of the great trochanter will pass through the middle of the head of the femur.
Inferiorly, of course, the trochanter is continuous with the shafl of the femur.
The lesser trochanter is a pyramidal process with a rounded ape* projecting backwards and inwards from the shaft about a hand's breadth below the top of the head; it forms a lever for the psoas muscle for the attachment of which its apex is roughened, while just below it is a rough surface for the iliacus.
The shaft is directed obliquely downwards and inwards, and the obliquity is slightly greater in the female than in the male. It is narrowest in the centre and widens above and below. In its middle third the shaft is prismatic, having an anterior, lateral, and medial surface and a posterior, lateral, and medial border; of these, the posterior border is very strong and rough, and is known as the linea aspera, while the other two borders are hardly noticeable.
In the upper and lower thirds the shaft becomes quadrilateral in section owing to the divergence of the lips of the linea aspera forming a posterior surface in addition to the other three.
The anterior surface of the femur begins above at the upper tubercle of the neck where the trochanteric line leaves the greater trochanter; in this triangular area the vastus lateralis is attached very strongly, but farther down the trochanteric line the vastus intermedius gains a short attachment, and still farther the vastus medialis, so that all three of these deep constituents of the quadriceps femoris are attached to the trochanteric line.
About the level ot the lesser trochanter the vastus intermedius occupies the whole of the anterior surface, which it continues to do until the lower third of the bone is reached, rising by a series of horizontal, fleshy strips with cellular tissue between them. Below the vastus intermedius the articularis genu takes origin from the anterior surface by two or more bundles.
The lateral surface attaches the vastus lateralis in its upper third and the vastus intermedius in its middle third.
The medial surface is singularly smooth, and has no muscle attached to it, but the vastus medialis plays over it and is separated from it by cellular tissue.
The posterior surface, as has been noticed, is only present in the upper and lower thirds of the shaft, being represented in the middh third by the linea aspera.
Fig. 220. — The Right Femur (Posterior View).
The linea aspera, although it attaches several lines of muscles, has a medial and a lateral lip, of which the latter is always the better marked, and again it may be well to repeat that the true linea aspera only occupies the middle third of the shaft and is only about 6 inches long. In its course will be seen one, or more often two, nutrient foramina which, as is usual in the lower limb, run away from the knee and, therefore, from the growing end of the bone.
Since the middle third of the femur is the densest mass of compact bone in the body it often remains after all the rest of the skeleton has disappeared, and for medico-legal or other purposes the side to which it belonged may usually be told by the nutrient foramina running upwards and the outer lip of the linea aspera being the more prominent.
Above the linea aspera divides into three or, in very well marked bones, four lines; these are, from within outwards: the spiral line, which winds round to the trochanteric line; the pectineal line, running to the lesser trochanter; the quadrate line, to the quadrate tubercle, though this line is only occasionally seen; and the gluteal tuberosity, passing upwards and outwards to the greater trochanter.
Below the linea aspera bifurcates and forms the lateral and medial supracondylar lines, of which the outer is well marked for the attachment of the short head of the biceps, while the inner ends below in the adductor tubercle, situated above the medial condyle. This inner line ^is particularly faint about a hand’s breadth above the top of the condyle, being rubbed out by the pressure of the femoral artery, which here passes into the popliteal space and becomes the popliteal artery.
The posterior surface of the femur, between the supracondylar lines, forms the popliteal surface, and is rough and covered by the fat which fills the popliteal space and separates the bone by \ inch from the popliteal artery. In the space, about a finger’s breadth above the medial condyle, is a rounded, rough elevation which attaches the medial head of gastrocnemius.
Ihe rather difficult attachments of the muscles to the back of the femur may now be studied, and perhaps the best method is to realize that there are six lines of muscular attachments. These are, from within outwards:
1. Ihe spiral line and medial lip of the linea aspera, attaching the vastus medialis.
2. Ihe pectineal line from the lesser trochanter to the linea aspera,
attaching the pectineus; and the linea aspera in the middle third of the lemur, attaching the adductor longus. »
3. A short line occupying the second quarter of the shaft, for the adductor brevis.
4. The feeble quadrate line, attaching the quadratus femoris, for I a out 2 inches below the quadrate tubercle, and, continuing this, the attachment of the adductor magnus, which runs right down to the adductor tubercle, with a break where the artery pierces it at the upper part of the medial supracondylar line.
5. The gluteal tuberosity, for the gluteus maximus, and, continuing this, the attachment of the short head of the biceps, which goes so high that sometimes the two muscles overlap, and below is attached to the lateral supracondylar line. It is this muscle which causes the outer lip of the linea aspera to be so well marked.
6. The lateral lip of the linea aspera, along which the vastus lateralis runs from the greater trochanter, following the gluteal tuberosity, to about the middle of the bone, and is then succeeded by the vastus intermedius, while at its lower end, just above the condyle, the plantaris is attached.
Fig. 221. — The Lower Extremity of the Right Femur.
Sometimes, on the lateral supracondylar line, a definite tubercle for a specially strong bundle of the biceps is formed.
It may be useful to recognise that the level of the lesser trochanter indicates the upper limit of attachment of the gluteus maximus and the adductor magnus.
The lower extremity presents an extensive articular surface, which is divided into three parts—anterior or patellar, and two posteroinferior or condylar. All three surfaces are continuous in front, but the condylar surfaces are widely separated behind by the intercondylar notch. The patellar surface is trochlear, and presents a vertical groove with a convexity on either side. The groove is to the inner side of the centre, and the part lateral to it is broader, more prominent, and extends higher than the medial part. The upper border is therefore sloped inwards and slightly downwards. The greater forward prominence of the outer part of the surface explains why the patella is inclined inwards in extension of the knee-joint and why it is not more often dislocated outwards.
The condyles are convex from before backwards and from side to side. Posteriorly they become prominent, and on this aspect the lateral condyle extends a little higher than the medial. As viewed from below the lateral condyle is broad and short, the medial being long and narrow. When the femur is held vertically the medial condyle projects lower down than the lateral, and this brings the two condyles upon the same horizontal plane when the bone occupies its natural sloping position. The outer border of the lateral condyle is very nearly in the same line with the outer border of the patellar surface, and the outer border of the medial condyle is in the same line with the inner border of the patellar surface. The inner border of the medial condyle has a convex outline, and at its anterior part it turns outwards to the patellar surface. For the most part the condyles are parallel, the exception being the front part of the medial condyle, which inclines outwards to meet the patellar surface.
Prom the above it will be realized that the antero-posterior axis of the lateral condyle is straight, while that of the medial is curved, with its concavity outward.
The demarcation between the condylar surfaces and the patellar surface is clearly marked at either side. The lateral condyle is separated from the patellar surface by a slightly elevated line and groove, extending outwards and slightly forwards from the front and outer part ot the intercondylar notch to the outer border of the cartilaginous surlace, where there is a depression which receives the anterior part ot the lateral semilunar fibro-cartilage during extension of the knee]°mt. The medial condyle is separated from the patellar surface by a me and groove, extending from near the front and inner part of the m ercondylar notch forwards and slightly inwards to the inner border ° i e * car thaginous surface, at a point about i inch below the inner end ot the upper border of the patellar surface. At this latter point ere is a depression which receives the anterior part of the medial semilunar fibro-cartilage during extension of the knee-joint. The line an groove just referred to do not extend quite close to the intercondylar 110 c ‘ subsides, but the line sweeps backwards in a curved
manner a ong the outer part of the inner condylar surface, thus marking o a narrow semilunar zone from the general tibial surface. This zone les c ose to the inner part of the intercondylar fossa, and is known as the semilunar patellar facet. ,
nrp J^ °J^ er / surface of the lateral condyle towards the back part E sen s , ^ lateral epicondyle, which gives attachment to the lateral i • * 1 j knee-joint. Immediately above and behind the j P - y e , V* a depression for the lateral head of gastrocnemius, and • j - f' l ow ^ there is a groove, called the popliteal groove, which a • f e ownwards and forwards. The tendon of the popliteus I
h iom e ront part of the horizontal portion of the groove, and it is lodged in the groove only when the knee is flexed; at other times it plays over the bevelled lower lip of the groove.
The inner surface of the medial condyle presents at its centre a large blunt eminence, called the medial epicondyle, for the attachment of the medial ligament of the knee. Posteriorly, where the medial supracondylar line joins the internal condyle, the adductor tubercle is situated, and the line of origin of the medial head of gastrocnemius extends upwards and outwards from this tubercle above the medial condyle.
Fig. 222. — Longitudinal Section through the Upper End of the Femur, Showing The Pressure Lamellie And Tension Lamellie.
The markings in connection with the intercondylar notch are for the cruciate ligaments. The impression for the anterior cruciate ligament is at the back part of the inner surface of the lateral condyle, whilst that for the posterior cruciate ligament is at the front part of the outer surface of the medial condyle, and adjacent portion of the front of the intercondylar notch. At the front of that fossa in the middle line the ligamentum mucosum is attached.
Structure. — The structure is that of a long bone. The medullary canal extends from a point just below the lesser trochanter to the level of the apex of the popliteal surface. Above and below these points the bone is composed of cancellated tissue, except externally, where there is a shell of compact bone. The cancellous tissue at the upper extremity has its lamellae arranged in a series of curves dispose( in three systems, one of which represents the pressure lamellae, anothe the tension lamellae, while the third, or bolting lamellae, run at righ angles to the others and transfer strain or stress. The pressure lamellc extend from the lower part of the neck and upper part of the shaf internally in a radiating manner, passing inwards to the head. Thi tension lamellae intersect the pressure lamellae almost at right angles and in many places render the presence of bolting lamellae unnecessary They run from the upper part of the shaft to the greater trochanter and thus carry the pull of the muscles from the trochanter to th< compact tissue. Additional strength is afforded by an almost vertically disposed plate of compact bone, called the calcar femorale, which run: upwards and downwards in front of, and above, the small trochanter and lies in the line in which weight is transmitted. The cancellou: tissue at the lower extremity has its lamellae arranged in vertical anc horizontal planes, the former being tension lamellae for the most part though those coming from the intercondylar notch will take th( traction of the crucial ligaments; the horizontal ones are obvious bolting lamellae.
Varieties. —(i) The lower part of the gluteal tuberosity may assume the fora of a depression, called the fossa hypotrochanterica. (2) There may be a thin trochanter, situated at the upper part of the gluteal tuberosity. (3) The line£ aspera may be unduly prominent, this condition being known as the pilasterec femur. (4) The amount of antero-posterior convexity of the shaft forward always noticeable, may be greatly exaggerated, and it is this condition whicl usually leads to pilastering. Antero-posterior bowing is usually found in ver} thick-set, muscular men. (5) Sometimes a femur is flattened and widened ir the upper part of its shaft. This is known as platymeria, and is much mon common in uncivilized and prehistoric races. There seems reason to associate it with a squatting posture. (6) The adductor tubercle may be unusually large and is then known as ‘ rider’s bone.’
The Femur of the Female. —(1) The bone is smoother and slightei than in the male. (2) The head is usually less than 45 mm. in diameter (3) The bones are farther apart above, more sloped inwards, and nearei to each other below, than in the male. (4) The lower end is usually less than 71 mm. in breadth.
Relation to Stature. —The femur is said to form 0*275 of the bod} stature, but in fifty cases examined in St. Thomas's, Guy's, and King's College dissecting rooms it was found to be 0*2725 in males and 0*270 m females. This was obtained from the maximal length of the femur: when it is measured in the oblique position which it occupies in the body its length is some 3 mm. less.
The men averaged 5 feet 6 inches (1,676 mm.), and the maxima] average length of their femurs was 456 mm., or just 18 inches. The women only average 5 feet 1 inch (1,550 mm.), and their femurs 416 mm., or 16J inches.
Usually one femur is longer than the other by 3 or 4 mm., and usually it is the left which is the longer.
Ossification. The femur ossifies in cartilage from one primary, and four secondary, centres. The primary centre appears at the middle of the shaft in the seventh week of intra-uterine life. The centre for the lower end appears nearly always before birth; in girls it may begin to form during the eighth (or even seventh) month, in boys in the eighth to ninth month, and even at or after birth in some rare but apparently full-time cases. The three upper epiphyses are cartilaginous at birth. The centre for the head appears in the first year, that for the greater trochanter at four (M.J or three (F.), while that for the lesser trochanter, which only forms the summit of the process, comes at ten or eleven, or perhaps a little later. The upper epiphyses join the shaft about eighteen (M.) or seventeen (F.), or a little earlier; the lower epiphyses join about nineteen or twenty (M.), in women about eighteen (variable). The neck is ossified from the centre for the shaft. The line indicating the junction of the lower epiphysis and shaft cuts the
adductor tubercle into two, one portion be- A p Pe a rs ,u SL uuu, longing to the lower epiphysis, and the other P and joins at 20 to the shaft. Fig. 22 3.—Ossification of the Femur.
The patella, or knee-cap, is situated in front of the knee-joint, where it articulates with the patellar surface in the femur. It is originally a. sesamoid cartilage developed in the tendon of the quadriceps femoris. The bone is triangular, with the apex downwards, and is compressed from before backwards. The superior border or base is broadband its plane is inclined forwards and slightly downwards. It gives insertion anteriorly to the rectus femoris and vastus intermedius from before backwards, and posteriorly it is covered by a portion of the synovial membrane of the knee-joint. The lateral borders are sloped towards the apex, the outer being at first rather more prominent than the inner. The outer border over its upper third gives insertion to a portion of the vastus lateralis, and the inner over its upper half to a portion of the vastus medialis. The apex is blunt, and, together with the adjacent marginal parts, gives attachment to the ligamentum patellae, by which the bone is connected with the tubercle of the tibia.
The anterior surface, which is slightly convex, is vertically ridged and covered by a prolongation of the tendon of the quadriceps femoris. It is perforated by numerous nutrient foramina, and is subcutaneous, being separated from the integument by the prepatellar bursa.
The posterior surface is divided into two parts—articular and nonarticular. The non-articular part represents the lower fourth, and is rough and depressed. It lodges a collection of fat covered by synovial membrane. The articular part corresponds with the upper three fourths, and is divided into two unequal parts by a round vertical ridge which is received into the groove of the patellar surface of the femur, The lateral division is broad and concave from side to side, whilst the medial is narrow and convex in the transverse direction. Excluding a narrow vertical zone at the inner part of the inner division, each division is subdivided by two slight transverse ridges into three horizontal zones—upper, middle, and lower, of which the middle is the largest and broadest. These six horizontal facets articulate with the patellar surface of the femur, the lower facets being in contact with the upper part of the patellar surface in extension of the knee-joint, the middle patellar facets with the middle portion of the patellar surface of the femur in semiflexion, and the upper patellar facets with the lower parts of the patellar surface of the femur in flexion of the knee-joint. The vertical zone at the inner part of the inner division of the articular surface (close to the inner border of the bone) constitutes a seventh facet. In extreme flexion of the knee-joint this facet articulates
Fig. 224. — The Right Patella. A, anterior surface; B, posterior surface.
with lunar facet on the outer part of the tibial surface of the medial condyle of the femur close to the intercondylar notch, whilst the
upper and outer horizontal facet is in contact with the front part of the lateral condyle.
Structure.— -The patella, being a short bone, is composed principally o c ense canceilous tissue with close meshes, surrounded by compact bone, which is much thicker in front than behind. The traction lamellae are specially marked in the front of the bone, while the pressure lamellae are at right angles to these to take the weight of the body in kneeling.
Ossification. —The original cartilage is deposited in the tendon of the quadriceps femoris in the third month of intra-uterine life. In this cartilage a single centre appears in the third year in girls, a little later in boys; ossification is completed about the age of puberty.
The tibia, or shin bone, is the inner and larger of the two bones of the leg, and alone transmits the weight of the body to the foot. The posterior surfaces of the shafts of the tibia and fibula are on the same horizontal plane above and below, but over about the middle threefifths the fibula projects slightly farther back on account of the anterior curvature of the tibia. Anteriorly the tibia is on a more anterior plane than the fibula, a point to be borne in mind in making flaps by transfixion. The tibia is a long bone, and is divisible into a shaft and two extremities, upper and lower.
The upper extremity, known as the head, is broader from side to side than from before backwards. Antero-laterally it is convex, but posteriorly it is rendered concave by the popliteal notch at its centre. The enlargements of the bone on either side of the head are called the condyles, lateral and medial. The lateral condyle is rather smaller than the medial, and at its posterior and under aspect it presents a flat circular facet, directed downwards, backwards, and outwards, which articulates with the head of the fibula. The cartilage of this facet is occasionally continuous with that of the lateral condylar surface. At the junctipn of the anterior and outer surfaces the lateral condyle has an elevation for the attachment of the ilio-tibial tract of the fascia lata, below which the extensor digitorum longus often gains a small attachment. The medial condyle is larger than the lateral, and has a distinct inclination backwards as well as inwards, a point to be noted in setting fractures of this bone. On its posterior aspect it presents a horizontal groove for the insertion of the chief portion of the tendon of the semimembranosus muscle. On the anterior aspect of the superior extremity, at the junction of the head and shaft, there is a well-marked projection, called the tubercle. It is fully i inch in length, and its upper border is about f inch below the level of the upper surface of the head. It is divisible into two nearly equal parts, upper and lower. The lower division is rough, and is usually strongly ridged in the vertical direction for the attachment of the ligamentum patellae. The upper division is smooth, and is separated from that ligament by a synovial bursa.
The superior surface of the head presents the two condylar articular surfaces, separated from each other by an irregular interval, which, amongst other markings, presents the bifid intercondylar eminence. Each surface surmounts the corresponding condyle. The lateral condylar surface is broad from side to side, and is almost circular. It is very slightly concave from side to side. Its cartilage rises towards the middle line to coat the lateral surface of the lateral intercondylar tubercle, and posteriorly it dips down for a little on the outer part of the back of the lateral condyle, where the tendon of the popliteus glides over it. It is in this situation that the cartilage is occasionally continuous with that of the fibular facet. The medial condylar surface is oval and decidedly more concave than the outer, being elongated from before backwards, but narrow from side to side. The cartilage of this surface rises towards the middle line to coat the medial surface of the medial intercondylar tubercle. Each condylar surface is deepened by a semilunar fibro-cartilage, which is placed round its peripheral part.
The interspace between the articular surfaces presents the intercondylai eminence, which is distant from the posterior border about
Anterior Horn of Medial Fibro-Cartilage Tubercle
Fig. 225. — The Head of the Right Tibia (Superior View).
one-third of the antero-posterior measurement. The intercondylar eminence is formed by an upward rising of the contiguous borders of the articular surfaces, and is bifid, ending in two tubercles, of which the medial is the better marked and longer of the two. The interspace between these tubercles gives attachment to the posterior horn of the lateral semilunar fibro-cartilage, which continues to be attached to a depression behind the lateral tubercle. The surfaces of the tubercles which face each other are free from cartilage, but the other surfaces have each a cartilaginous covering.
In front of the eminence there is a rough depression where important structures are found; in front of the lateral intercondylar tubercle the anterior horn of the lateral semilunar fibro-cartilage is attached, V* ^ ron f °f the medial tubercle the anterior cruciate ligament is attached to the bone. At the extreme anterior and inner part there is an impression for the anterior horn of the medial semilunar fibrocartilage. On the outer side of the impression for the anterior cruciate ligament, and in front of that for the anterior horn of the lateral semilunar fibro-cartilage, there is a depression which is partially occupied by a small collection of fat. At its outer part, however, there is a groove which receives a portion of the lateral semilunar fibro-cartilage in extension of the knee-joint. The immediately adjacent portion of the lateral articular surface is specially faceted for the play of part of the lateral condyle of the femur in extension of the joint. Behind the intercondylar eminence there is a more limited rough depression, which leads backwards to the popliteal notch. The posterior horn of the medial semilunar fibro-cartilage is attached to the inner part of this depression, and the posterior cruciate ligament is attached to its back part, as well as to the popliteal notch.
Order of Structures attached to the Head. —The structures, enumerated as nearly as possible in order from before backwards, are as follows:
1. Anterior horn of medial semilunar fibro-cartilage.
2. Anterior cruciate ligament.
3. Anterior horn of lateral semilunar fibro-cartilage.
4. Posterior horn of lateral semilunar fibro-cartilage.
5. Posterior horn of medial semilunar fibro-cartilage.
6. Posterior cruciate ligament.
The head is pierced all round by many nutrient foramina for branches of the inferior genicular arteries of the popliteal, and of the posterior and anterior tibial recurrents of the anterior tibial.
The shaft is massive and prismatic. It diminishes in size from above downwards over its upper two-thirds, and then gradually enlarges towards its lower end. It presents three borders and three surfaces. The anterior border extends from the outer side of the tubercle above to the anterior margin of the medial malleolus below. Over the upper two-thirds, where it occupies the middle line, it is prominent, and is known as the crest or shin-ridge. This is doubly curved, the convexity of the upper curve being directed inwards, and that of the lower outwards. Over the lower third the anterior border inclines inwards, and the lateral surface of the shaft is thus allowed to come forwards. The crest is subcutaneous, and gives attachment to the deep fascia of the leg. The medial border extends from the inner and back part of the medial condyle to the posterior margin of the medial malleolus. For 3 or 4 inches superiorly it is rough, and gives attachment to the medial ligament of the knee-joint. Over its middle third it is prominent, and it here gives origin to a portion of the soleus as low as the centre of the bone. The lateral or interosseous border extends from the front of the fibular facet above to a point about 2 inches from the lower end, where it bifurcates. The two divisions pass to the front and back of the fibula, and enclose between them a rough triangular surface for the interosseous tibio-fibular ligament. This border is sharp and wiry, and gives attachment to the interosseous membrane,
Fig. 226. — The Right Tibia Medial Malleolus and Fibula (Anterior View).
The medial surface is situated between the crest and medial border. It is for the most part subcutaneous, and slightly convex. Superiorly, where it becomes expanded and flattened, it presents a vertical rough area, behind the tubercle, for the insertion of the sartorius, and behind this two vertical rough impressions in the same line with each other, the upper of which gives insertion to the gracilis, and the lower to the semitendinosus. The lateral surface is situated between the crest and interosseous border. It is concave over its upper two-thirds, where it gives origin to the tibialis anterior. Over the lower third, where it is convex, it turns to the front and supports the extensor tendons, and anterior tibial vessels and nerve. Th e posterior surface lies between the interosseous and medial borders. Superiorly it is crossed by the soleal or oblique line , which is rough, and extends from the fibular facet downwards and inwards to the medial border at about the junction of the upper third and lower two-thirds. This line gives attachment to the popliteal fascia and part of the soleus, whilst the triangular popliteal surface above gives insertion to the popliteus muscle. The posterior surface below the soleal line presents over its middle third the vertical line which divides it into two parts. The outer portion is narrow, and gives origin to the tibialis posterior as low as a point just below the centre of the bone. The inner portion is broad, and gives origin to the flexor digitorum longus over the middle two-fourths of the bone. A little below the soleal line, close to the outer side of the vertical line, is the nutrient foramen for a large branch of the posterior tibial artery. This foramen, which is the largest of its class, and the canal to which it leads are directed downwards. The posterior surface in its lower third supports the flexor tendons, and posterior tibial vessels and nerve.
The lower extremity is cuboidal, and below presents a quadrilateral articular surface, concave from before backwards, and wider in this direction laterally than medially. It is broader in front than behind, and articulates with the superior surface of the talus. The posterior border projects somewhat lower than the anterior. The anterior surface, immediately above the anterior border, is depressed for the anterior ligament of the ankle-joint, and just above this has a transverse, rounded ridge marking the position of the epiphysial line. The posterior surface gives attachment to the posterior ligament of the ankle-joint as far inwards as the groove behind the medial malleolus. It presents the following grooves: one, very faint, for the tendon of the flexor hallucis longus near the outer end; and one, mainly situated on the back of the medial malleolus, for the tendons of the tibialis posterior and flexor digitorum longus.
The inner aspect of the lower extremity presents the medial malleolus, which is a strong process having a downward direction. Its medial surface is rough, convex, and subcutaneous. The lateral surface is covered by cartilage, continuous with that which coats the lower extremity. The plane of this surface is vertical, and the cartilage
oats it more deeply in front than behind. It articulates with the
Semimembranosus J V Popliteal Notch
Styloid Process of Fibula
Medial Condyle of Tibia
Popliteal Surface and Popliteus
Flexor Hallucis Longus —' Nutrient Foramen
_ Peroneus Brevis
Tip of Medial Malleolus Groove for Tibialis Posterior and Flexor Digitorum Longus
Tip of Lateral Malleolus
Groove for Flexor Hallucis Longus
Fig. 27. The Right Tibia and Fibula (Posterior View)
medial surface of the talus. The anterior border is rough and round for the attachment of the anterior and medial ligaments of the anklejoint. The lower border is indented by the fibular notch, in front of which is the projection known as the tip, the medial ligament being attached to both of these parts. Posteriorly is the groove for the tendons of the tibialis posterior and flexor digitorum longus. The outer aspect of the lower extremity may show a concave facet for the fibula, and above this a concave triangular rough surface about ij inches long for the interosseous tibio-fibular ligament.
The inferior extremity of the tibia has many nutrient foramina.
Structure.—The structure is that of a long bone. The medullary canal extends above to a point about ij inches below the lower margin of the anterior tuberosity, and interiorly to a point about 1 inch below the lower extremity of the crest. The cancellous lamellae display the characteristic arrangement of pressure and bolting lamellae, and during the whole of life the positions of the epiphysial lines are indicated by a greater density of the tissue.
App ears just before birth, and joins about 22
May appear about the 12th year, and joins soon thereafter
Appears in the 7th week (intra-uterine)
Varieties. —(i) The tibia is sometimes much compressed laterally, which leads to an increase in its antero-posterior diameter. In these cases the vertical line posteriorly becomes unduly prominent, a condition which is associated with a large development of the tibialis posterior muscle. Such a bone is spoken of as being platycnemic, and the condition is known as platycnemia. (2) The anterior aspect of the lower extremity of the bone sometimes presents a pressure facet at its auter part for articulation with the upper surface of the neck of the talus in extreme flexion of the ankle-joint. This frequently accompanies platymeria and platycnemia.
(3) Retroversion of the head of the tibia and
(4) great torsion of the shaft are met with especially in prehistoric bones.
Ossification. —The tibia is ossified in cartilage from one primary and three secondary centres.
The primary centre appears at the centre af the shaft about the seventh week. The three secondary centres are disposed as follows: two are superior, one for the head, and the other for the tubercle; and one is inferior for the lower extremity and medial
malleolus. Upper Extremity. —The centre for the head appears just after birth, or at this time (M.), or before birth (F.). The epiphysis extends down in front to include the tubercle; this may become ossified totally by extension of the epiphysial centre, or an additional centre may appear in its lower rough part about the age of twelve. The whole epiphysis joins the shaft about nineteen to twenty (M.), or in women seventeen to eighteen. Lower Extremity. —The centre for the lower extremity and medial malleolus appears towards the end of the second year, and this lower epiphysis joins about the eighteenth year (M.) or sixteenth to seventeen (F.).
Appears at end of 2nd year and joins about 18
Fig. 228. — Ossification of the Tibia.
The fibula, or peroneal bone, is situated on the outer side of th tibia. It is very slender for its length, and is a rudimentary bone It takes no part in transmitting the weight of the body, but serve chiefly to afford attachment to muscles, though it also forms part 0 the ankle-joint, and acts as a brace or support to the tibia. It is ; long bone, and is divisible into a shaft and two extremities, upper an< lower.
The upper extremity, or head, is cuboidal, its upper surface beinj somewhat flattened and sloping. It is situated about f inch belo\ the level of the head of the tibia. Posteriorly it is prolonged upward into the styloid process, to the tip of which the lateral ligament of th< knee-joint is attached. In front of this process the upper surface o the head is sloped downwards and forwards, and is divisible into ai articular and a non-articular part. The articular division is media in position, and takes the form of a flat circular facet, which is directe( upwards, inwards, and forwards, to articulate with the facet on th< posterior and under aspect of the lateral condyle of the tibia, by whicl latter it is overhung. The non-articular division is lateral in position and takes the form of a rough depression, into which the tendon o the biceps femoris, previously divided into two parts by the ligamen of the knee, takes insertion. Posteriorly the head gives origin to th< soleus. Laterally it gives origin to the peroneus longus, and a a point nearly | inch anterior to the styloid process its outer margir gives attachment to the lateral ligament. Anteriorly it gives origir to the extensor digitorum longus. The constricted part below th( head is called the neck.
The lower extremity is prolonged downwards into a massive pro jection, called the lateral malleolus, which is not only larger, but lowei down and farther back, than the medial malleolus. It is pyramidal the base being directed upwards. The lateral surface is rough, convex and subcutaneous. The medial surface is divisible into two parts articular and non-articular. The articular division is anterior in position, and occupies about two-thirds of the surface. It is triangular with the apex downwards, and it mainly articulates with the outei surface of the talus. Superiorly, however, for about J inch it occasionally assumes a somewhat semilunar outline, and this portion maj articulate with the lateral aspect of the tibia. The non-articular divisior is posterior in position, and occupies about one-third of the surface. It is rough and depressed, and is known as the malleolar fossa. Superiorly the posterior ligament of the ankle-joint and inferiorly the posterior fasciculus of the lateral ligament of the ankle-joint are attached to the posterior margin of this fossa. Above the lateral malleolus on the inner aspect there is a rough, convex, triangular surface with its apex upwards, about ij inches long, for the interosseous tibio-fibular ligament. The anterior border projects at first forwards, and then slopes downwards and backwards to the tip. The projecting part gives attachment to the anterior tibio-fibular ligament, and the lower portion of the sloping part to the anterior fasciculus of the lateral ligament of the anklejoint. To the anterior border, just in front of the apex, the middle fasciculus of the lateral ligament is attached.
The posterior surface is shorter than the anterior, and is vertical. It presents the peroneal groove for the tendons of the peroneus longus and peroneus brevis.
The shaft is slightly curved, the convexity being directed backwards in the upper part, and inwards lower down. It is quadrilateral in section in its upper three-fourths, where it presents four borders and four surfaces, but it is somewhat triangular in the lower fourth. The anterior border , which is the most prominent, commences in front of the head, and passes straight downwards until it reaches the lower fifth, where it turns outwards and backwards and bifurcates. One division passes to the anterior margin of the lateral malleolus, and the other to the posterior margin, lateral to the peroneal groove. These two divisions enclose between them a triangular area which is continuous with the outer surface of the lateral malleolus. This border gives attachment to the anterior intermuscular septum. The anterior medial or interosseous border, which gives attachment to the interosseous membrane, also commences in front of the head, where it is very near the anterior border. As it descends it keeps near to that border at first, but beyond the upper third it gradually diverges from it, and on reaching a point about 2 inches above the lateral malleolus it bifurcates. One division passes to the anterior margin of the malleolus, becoming incorporated with one of the divisions of the anterior border to the posterior margin of the malleolus, whilst the other passes medial to the upper end of the peroneal groove. The two divisions, as they diverge, enclose a rough triangular area, which is slightly convex and gives attach ment to the interosseous tibio-fibular ligament. The postero-media border commences on the inner side of the head, not far from th< interosseous border. It descends in a backwardly-curved manner gradually leaving the interosseous border, but subsequently approaching it, until on reaching the junction of the upper two-thirds and lowe third it ends by joining it. This border gives attachment to an inter muscular septum, which separates the tibialis posterior from the soleu: and flexor hallucis longus. The posterior border extends from th< back of the head to the back of the lateral malleolus, medial to th< peroneal groove, and in its lower part it turns inwards. It give: attachment to the posterior intermuscular septum.
. 229.—The Right Fibula (Medial Aspect).
The anterior surface is situated between the anterior and interosseou: borders. It is very narrow over about its upper half, but become: wider below. It gives origin over about its upper three-fourths to th< extensor digitorum longus, over its lower fourth (except about 1 incl below) to the peroneus tertius, and over about its middle two-fourth: to the extensor hallucis longus, which is nearest to the interosseou: border. The medial surface is situated between the interosseous anc postero-medial borders. It is concave and fusiform, being narrow above and below, but wide at the centre, and it gives origin to th( tibialis posterior. On this surface the oblique line of the fibula , foi attachment of a tendinous plate of origin in the tibialis posterior, run' obliquely downwards and backwards. The posterior surface is limitec by the postero-medial and posterior borders, and in its lower fourtt it undergoes a twist, and turns round to become internal. Over it' upper third it gives origin to a part of the soleus, and over its lowei two-thirds, except the last inch or more, to the flexor hallucis longus A more or less distinct groove for the peroneal artery may often be seen on this surface. The lateral surface lies between the anterior and posterior borders. It is the broadest, and in muscular subjects is deeply grooved over rather more than its upper half. Inferiorly it undergoes a twist, and turns round to become posterior, where it leads directly to the peroneal groove on the back of the lateral malleolus. In this manner the two peroneal tendons are guided to this groove. The upper two-thirds of this surface give origin to the peroneus longus, and the lower two-thirds, except the last 2 inches, to the peroneus brevis, these two muscles overlapping towards the centre of the bone.
The nutrient foramen, which is small, is usually situated on the posterior surface, but may be on the medial, a little above the centre, and there may be an additional one a little higher up. It is for a branch of the peroneal artery, and the direction of the foramen and the canal to which it leads is downwards towards the ankle.
Articulations .—Superiorly with the lateral condyle of the tibia, and inferiorly with the outer aspect of the tibia, and the lateral surface of the talus.
Appears about the 4th Year, and joins about 23
Structure. — The structure is that of a long bone, and the medullary canal is limited to about the middle three-fifths of the shaft.
Varieties, (i) There may be a small facet at the antero-superior angle of the articular facet for the talus, articulating with the tibia. (2) The oblique line may be double. (3) The peroneal surface may be very concave, forming the ‘ channelled fibula.’
Ossification. —The fibula ossifies in cartilage from one primary, and two secondary, centres. The primary centre for the shaft appears in the seventh week of mtra-uterine life. At birth the shaft is ossified, but the extremities are cartilaginous. The centre for the lower extremity appears in the second year, and that for the upper extremity about the fourth year. Both centres are earlier in girls. The lower epiphysis joins the shaft about eighteen, and the upper about twenty, girls being one to two years earlier. The fibula forms no exception to the general law of ossification applicable to long bones with an epiphysis or epiphyses at either end, which may be here restated as follows: ‘ The epiphysis or epiphyses, at the end towards which the nutrient foramen and the canal to which it leads are directed, are the last to show signs of ossification .’ It does, however, form an exception to the less constant coincidence that the epiphysis which joins last, and is therefore at the growing end of the bone, appears first.
The law seems to be that the end which has the larger mass of cartilage develops a centre of ossification first, and usually this larger mass is at the growing end of the bone. In the fibula, however, the cartilaginous mass of the malleolus is greater than that of the head, though this has been acquired recently, and is a human characteristic.
At about the seventh month of intra-uterine life the tibial and fibular malleoli are of nearly equal proportions, but by the second year, previous to the appearance of its centre of ossification, the fibular malleolus has attained the large relative size which characterizes it throughout life.
Fig. 230.—Ossification of the Fibula.
The tarsus is composed of seven short bones—namely, the talus, calcaneum, navicular, three cuneiforms, and cuboid.
The first two constitute the proximal row, the talus lying above the calcaneum, and the last four comprise the distal row, the order from the inner or tibial to the outer or fibular side being medial, intermediate, and lateral cuneiform bones, and cuboid. The navicular occupies an intermediate position.
The talus, or astragalus, is characterized by having a head, neck, and body. It is situated between the tibia above and the calcaneum below, is grasped laterally by the tibial and fibular malleoli, and has the navicular in front. It is the only tarsal bone which receives directly the weight of the body, and it lies with its long axis directed forwards and inwards. In point of size it comes next to the os calcis.
The head forms the anterior part of the bone, and presents an extensive convex articular surface, which looks forwards and also downwards. It is divided into three facets, called navicular, calcaneal, and ligamentous. The navicular facet , which is placed on the anterior surface, is pyriform, and its long axis is directed downwards and inwards. The calcaneal facet, which may be subdivided (see Fig. 231, B), continuous with the foregoing, is situated on the inferior surface. It is convex and elliptical, and its long axis is directed forwards and outwards. It is often crossed by an elevated ridge a little anterior to the centre, which may divide it into two, and it articulates with the sustentacular facet on the upper surface of the calcaneum. The ligamentous facet is situated on the inner aspect of the inferior surface, and is in contact with the superior surface of the plantar calcaneonavicular or ‘ spring ’ ligament.
The neck is the constricted part behind the head. It is conspicuous superiorly, and passes inferiorly into the interosseous groove. This groove is directed forwards and outwards, its inner part being narrow and deep, and the outer wide and shallow. It gives attachment to the strong interosseous talo-calcaneal, which binds the talus to the os calcaneum. The neck is perforated all round with numerous nutrient foramina for offsets of the dorsalis pedis artery and its tarsal branch.
The body is cuboidal, and has six surfaces. The superior surface presents an extensive trochlear facet, which is concave from side to side, and convex from before backwards. Posteriorly it slopes downwards, and its outer border is bevelled for the play of the transverse tibio-fibular ligament. The inner border is straight and slightly depressed, and as a rule it extends rather farther back than the outer. The surface is broader in front than behind. The lateral surface is deep, and has a large triangular facet for the lateral malleolus, the apex being downwards. It is concave from above downwards, and, immediately in front of it, the anterior fasciculus of the lateral ligament of the ankle-joint takes attachment. The medial surface presents superiorly a sickle-shaped facet, broad in front and pointed behind, for the medial malleolus. This facet in the foetus encroaches on the inner side of the neck, a condition which is associated with the inversion of the foot at that period of life. This sometimes occurs in the adult, and, if it does so to any marked extent, it usually accompanies the condition known as talipes varus. The inferior surface presents a large oval facet, concave from within forwards and outwards, for articulation with the calcaneum. The posterior surface is short, stout, and oblique, its direction being inwards and forwards. It presents a groove, which is directed downwards and inwards, for the tendon of the flexor hallucis longus. On either side of this groove there is a tubercle, the medial being rudimentary, whilst the posterior is well developed and gives attachment superiorly to the posterior fasciculus of the lateral ligament of the ankle-joint.
Articulations. — Superiorly, with the shaft, and medially with the medial malleolus, of the tibia; laterally with the lateral malleolus of the fibula; inferiorly with the calcaneus; anteriorly with the navicular, and occasionally with the lower and inner angle of the cuboid.
Fig. 231.—- The Right Talus. A, superior view; B, inferior view.
Structure. The talus, being a short bone, is composed of cancelf^ 1SSue ’ surrou nded by a thin shell of compact bone. The lamellae 01 the cancellated tissue are arranged in a curved manner, and in two sets. Some pass downwards and backwards from the superior surface 0 the posterior calcaneal facet, whilst others arch downwards and orwards from the superior surface to the neck, these being the directions in which weight is transmitted.
Varieties.— (i) The posterior tubercle on the posterior border may form ; separate ossicle, called the os trigonum. (2) There may be a facet on the uppe surface of the neck at its outer part, due to forcible contact with the anterio; margin of the lower end of the tibia. This facet is always present in the foetus and usually persists in squatting races.
The calcaneum, or os calcis, is the largest bone of the tarsus, anc is characterized by its elongation, lateral compression, and enlarge ment posteriorly into a tuberosity. It is situated below the astragalus and behind the cuboid, where it lies with its long axis directed forward: and outwards. It presents two extremities and four surfaces.
The posterior extremity, which is enlarged, forms the tuberosity or tuber calcis , and constitutes the prominence of the heel. Posteriori} it is divided into three zones—an upper, which is smooth and separatee from the tendo calcaneus (Achillis) by a bursa; a middle, rough anc vertically ridged, for the insertion of the tendo calcaneus (Achillis); anc a lower, which is continuous with the tubercles on the plantar aspect and supports the fat of the heel.
The anterior extremity presents a large, somewhat triangular facet narrow towards the sole, which is concave from above downwards and outwards, and convex from side to side, for articulation with the cuboid.
The superior surface presents over its anterior part two facets for the talus, separated by an oblique groove, and posteriorly a nonarticular surface. The antero-medial or sustentacular facet surmounts the sustentaculum tali. It is concave and somewhat elliptical, its long axis being directed forwards and outwards. It is often constricted in front of the centre, and is sometimes broken up into two facets by a rough groove. The postero-lateral facet is large, oval, and convex from behind forwards and outwards, and is directed as much forwards as upwards. The intervening groove, which is directed forwards and outwards, becomes wide and shallow laterally, and in front of the outer part of the groove the upper surface gives origin to a portion of the extensor digitorum brevis and the inferior extensor retinaculum. When the talus is in position this groove is converted into a short canal called the tarsal tunnel , widening into the sinus tarsi. The groove is occupied by the interosseous ligament and the sinus by the Y-shaped part of the inferior extensor retinaculum and the origin of the extensor digitorum brevis. The superior surface behind the articular portion is rough, and supports a collection of fat.
The plantar surface is narrow and rough. Posteriorly it presents two tubercles, the lateral of which is small but prominent, whilst the medial is large and blunt. The lateral tubercle gives attachment to the lateral division of the plantar aponeurosis, and a portion of the abductor digiti minimi, whilst the inner gives attachment to the central and medial divisions of the plantar aponeurosis, the outer part of the abductor hallicus, the flexor digitorum brevis, and a portion of the abductor digiti minimi. The greater part of the plantar surface gives attachment to the long plantar ligament, and anteriorly it presents a small round eminence, called the anterior tubercle, to which the short plantar ligament is attached.
The medial surface is concave, and is overhung at its anterosuperior part by the sustentaculum tali . This latter is concave and articular above for the talus, and below it presents a groove for the flexor hallucis longus. Anteriorly it gives attachment to the plantar calcaneo-navicular ligament, below which a slip of the tibialis posterior is attached, and its inner margin gives attachment to fibres of the medial ligament of the ankle-joint, while its inner margin is grooved by the tendon of the flexor digitorum longus. It is worth while noticing carefully the relation of the sustentaculum tali to the thre long tendons: the flexor hallucis longus below it, the flexor digitorun longus on a level with it, and the tibialis posterior above it. Tb general concavity of the medial surface of the calcaneum is in contac with the plantar vessels and nerves, and anteriorly it affords origin t< the inner head of the flexor accessorius.
Fig. 232. — The Right Calcaneum. A, superior aspect; B, medial aspect.
The lateral surface is somewhat convex. Towards its anterio: and lower part it may present a short oblique ridge, called the peronea tubercle , which separates two grooves. The upper groove transmit* the tendon of the peroneus brevis, and the lower that of the peroneu* longus. There is a small tubercle, about the centre of the surface for the middle fasciculus of the lateral ligament of the ankle-joint.
Articulations. — Superiorly with the talus and anteriorly with the cuboid.
Structure. —The structure is that of a short bone. Some of the pressure lamellae of the cancellated tissue arch downwards and backwards from the large postero-lateral facet on the superior surface to the prominence of the heel, others pass forwards from this facet to direct the pressure to the facet for the cuboid; while traction lamella pass from the point of attachment of the tendo calcaneus forwards and downwards to the lower surface of the bone.
Varieties. —(i) Ossification of plantar aponeurosis extending from the media] posterior tubercle. (2) Variability of development of the peroneal tubercle. (3) Occasional synostosis with cuboid.
Ossification. —-The os calcis ossifies in cartilage from one primary, and one secondary, centre. The primary centre appears in the sixth month of intrauterine life. The secondary centre appears in the tenth year or earlier, and forms a thin epiphysial scale over the posterior surface of the tuber calcis, which joins in the fifteenth (F.) to eighteenth (M.) years. This epiphysis includes the outer, and a large part of the inner, tubercle on the under surface, and only occupies the lower two-thirds of the posterior surface, forming a typical traction epiphysis.
The navicular or scaphoid bone is distinguished by its resemblance to a boat. It is situated on the inner side of the foot, where it is placed in front of the talus, and behind the three cuneiform bones. It is compressed from before backwards, and its long axis is directed inwards and downwards. The anterior surface presents a large convex articular surface, divided into three facets by two ridges which converge inferiorly. The inner facet, for the medial cuneiform, is pyriform, with the narrow end upwards. The middle facet, for the intermediate cuneiform, is triangular, with the truncated apex downwards. The outer facet, for the lateral cuneiform, resembles the middle, except that it is rather shorter and has a rounder apex. The posterior surface is characterized by a large concave, pyriform facet for the front of the head of the talus, its narrow end being directed downwards and inwards. The dorsal surface , extensive and rough, is sloped downwards and inwards. The plantar surface, narrow and rough, gives attachment to the plantar calcaneo-navicular ligament, and about its centre there is usually a knob-like projection, called the ligamentous tubercle , and between this and the tuberosity is usually a groove lodging one of the expansions of the tibialis posterior tendon. The lateral surface is broad and rough, and it sometimes presents a small facet for the cuboid, contiguous to the outer facet on the anterior surface. The inner extremity (prow of the boat) is inclined downwards, and forms a stout, round projection on the inner side of the sole, called the tuberosity, which gives insertion to the principal portion of the tendon of the tibialis posterior.
Fig. 233. —The Right Navicular Bone. A, postero-superior view; B, antero-inferior view.
Articulations. — Posteriorly with the talus, anteriorly with the three cuneiform bones, and sometimes with the cuboid laterally.
Structure. —The structure is that of a short bone.
Variety. —The tuberosity sometimes forms a separate ossicle.
The Cuneiform Bones
The cuneiform bones are three in number—namely, medial, intermediate, and lateral. They are situated between the navicular and the inner three metatarsal bones, and are characterized by their wedge shape. The medial cuneiform is the largest, and the intermediate is the smallest.
The medial cuneiform bone is situated on the inner side of the foot where it lies with the narrow end of the wedge upwards, and it supports the first metatarsal. The dorsal surface is narrow and rough. The plantar surface is thick and convex, and posteriorly it presents an eminence for a slip of the tendon of the tibialis posterior. The medial surface is traversed by an oblique facet, directed downwards and forwards, for the tendon of the tibialis anterior, the principal portion of which is inserted into an impression situated at its lower part. The lateral surface presents, close to its superior and posterior borders, an L-shaped facet for the intermediate cuneiform, at the anterior extremity of which there is a small facet for the inner side of the base
Fug. 234. — The Right Medial Cuneiform Bone. A, medial aspect; B, lateral aspect.
o. the second metatarsal. The rest of the surface is concave and rough or strong ligaments, except at the lower and anterior part, where it gives insertion to a slip of the tendon of the peroneus longus. The an error surface is deep, and presents a convex reniform facet for the rs metatarsal, the concave border being directed outwards. The pos error surface much smaller than the anterior, is characterized by a concave pyniorm facet for the navicular, the narrow end being
Articulations. Posteriorly with the navicular, anteriorly with the
rs metatarsal, and laterally with the intermediate cuneiform and second metatarsal.
Variety. —The medial cuneiform may be divided partially or completely into two parts, dorsal and plantar.
The intermediate cuneiform bone lies with the broad end of the wedge upwards, and it supports the second metatarsal. The dorsal surface is rough and nearly square. The plantar surface, also rough, is narrow, and gives insertion to a slip of the tendon of the tibialis posterior. The medial surface presents, close to its superior and posterior borders, an L-shaped facet for the medial cuneiform, the remainder of the surface being rough and ligamentous. The lateral surface has a vertical facet posteriorly for the lateral cuneiform, and elsewhere it is rough and ligamentous. The anterior and posterior surfaces are triangular and covered by cartilage, the former articulating with the second metatarsal, and the latter with the navicular. They are distinguished from each other in the following manner: the anterior surface is convex, whilst the posterior is concave; the apex of the anterior surface is more pointed than that of the posterior; and the posterior surface, rather broader than the anterior, has one of the limbs of the L facet close to it.
Fig. 235. —The Right Intermediate Cuneiform Bone. A, medial aspect; B, lateral aspect.
The intermediate cuneiform is sometimes considered a difficult bone to determine the side of the body to which it belongs. As a matter of fact, it may be done quite easily by the finger alone if it is noticed that the posterior articular facet is more concave than the anterior; and the inner surface, which fits into the concavity of the medial cuneiform, is correspondingly convex.
Articulations. — Posteriorly with the navicular, anteriorly with the second metatarsal, medially with the medial cuneiform, and laterally with the lateral cuneiform.
The lateral cuneiform bone, like the middle, lies with the broad end of the wedge upwards, and it supports the third metatarsal. The dorsal surface is rough, quadrilateral, and elongated from before backwards. The plantar surface, also rough, is narrow, and gives insertion to a slip of the tendon of the tibialis posterior. The medial surface presents a vertical facet posteriorly for the intermediate cuneiform, and two semi-oval facets anteriorly for articulation with the proximal pair of facets on the outer side of the base of the second metatarsal.
The remainder of the surface is rough and ligamentous. The later & surface has a large, almost circular, facet near the postero-superioi angle for the cuboid, and there may be a small semi-oval facet at the antero-superior angle for the inner side of the base of the fourth metatarsal, but this facet is not constant. Elsewhere the surface is rough
Fig. 236. —The Right Lateral Cuneiform Bone. A, medial aspect; B, lateral aspect.
For 4th Metatarsal (inconstant)
__ For Cuboid
Anterior Surface for 3rd Metatarsal
and ligamentous. Ihe anterior and posterior surfaces are triangular, and covered by cartilage, the former articulating with the third metatarsal, and the latter with the navicular. They are distinguished from each other in the following manner: the anterior facet is deeper than the posterior, and its apex is more pointed; the cartilage of the anterior surface extends over its entire length, but the lower part of the posterior
Fig. 237. The Right Cuneiform Bones (Antero-superior View).
fmm < hplm i n0n ' ar ^^ U ^ r ’ an ^ ei 'i c ? r * ace t is slightly concavo-convex almost rirnd^f but }^ e P osterior is concave, and it has the large, Artioniaf* ar * fac ^ 0n the lateral surface contiguous to it. third mpta + 10 n Sj> Posteriorly' with the navicular, anteriorly with the side of thp if rSa > medially with the intermediate cuneiform and outer ase 0 ^ ie sec °nd metatarsal, and laterally with the cuboid, and, it may be, with the inner side of the base of the fourth metatarsal.
Structure of the Cuneiform Bones.— The structure of each is that of a short bone.
When the cuneiform bones are in position their posterior surfaces are on the same transverse plane, but the anterior surfaces of the medial and lateral project farther forwards than that of the intermediate. In this manner a recess is formed, into which the base of the second metatarsal bone is received.
The Cuboid Bone
The cuboid bone is characterized by its irregularly cubical shape, and by the groove and ridge on its plantar aspect. It is situated on the outer border of the foot, where it lies between the calcaneum and the fourth and fifth metatarsal bones. The anterior surface has its cartilage divided by a vertical ridge into two facets—an inner quadrilateral for the fourth metatarsal, and an outer triangular for the fifth metatarsal. The posterior surface presents a large, somewhat triangular facet, narrow towards the sole and deep medially. It articulates with the calcaneum, and its medial and inferior angle, called the calcaneal process, projects backwards for a little beneath that bone. Below and inside the calcaneal process there may be a facet for the head of the talus. The medial surface, which is extensive and vertical, presents a large, almost circular, facet for the lateral cuneiform, near the centre and extending to the dorsal surface. Behind this, and usually continuous with it, there may be a small facet for the navicular, the remainder of the surface being rough for ligaments. The lateral surface is very short and narrow, and presents a notch leading to the peronea groove on the plantar surface. The dorsal surface is rough, and i directed upwards and outwards. The plantar surface has in front th deep peroneal groove, which is directed inwards and forwards, an< lodges the tendon of the peroneus longus in certain positions of th foot. Behind the groove is a stout, oblique ridge for the long planta ligament. This ridge becomes enlarged laterally into the tuberosity which is covered by cartilage on its anterior and outer aspects for th play of the sesamoid cartilage, usually present in the tendon of th peroneus longus. The surface behind the ridge gives attachment t< the short plantar ligament, a slip of the tendon of the tibialis posterior and some fibres of the flexor hallucis brevis, but the latter may sprinj from the medial surface.
Fig. 238. —The Right Cuboid Bone. A, lateral aspect; B, medial aspect.
Articulations. —Posteriorly with the calcaneum, anteriorly with th' fourth and fifth metatarsal bones, medially with the lateral cuneiform and sometimes with the navicular, and at the lower and inner angli occasionally with the talus.
The tarsus as a whole is convex superiorly, and concave inferiorly from before backwards as well as from side to side. The part in from of the talus and calcaneum constitutes the instep, and the entire tarsui forms two arches—an inner, comprising the calcaneum, talus, navicular and three cuneiform bones; and an outer, formed by the calcaneum and cuboid.
Varieties. —The number of tarsal bones is sometimes increased to eight, whicl is brought about in one or other of the following ways: (i) The posterior tubercli on the posterior border of the astragalus may form a separate ossicle, callec the os trigonum; (2) the tuberosity of the navicular may form a separate ossicle
(3) the medial cuneiform may be divided into two parts, dorsal and plantar; o:
(4) there may be an additional ossicle in the space at the antero-medial part o the calcaneum, or between the medial cuneiform and the second metatarsal.
Ossification. —The tarsal bones ossify in cartilage, each from one centr( (except the os calcis, which has one primary, and one secondary, centre), anc at the following periods approximately:
Calcaneum, 6th month (intra-uterine). Lateral cuneiform, 1st year.
Talus, 7th month (intra-uterine). Medial cuneiform, 3rd year.
Cuboid, 9th month (intra-uterine). Intermediate cuneiform, 4th year.
Navicular, 4th year.
All these times may be much earlier in female children.
The metatarsus is composed of five long bones, which are named numerically from within outwards, that of the great toe being the ^ rs |‘ Each bone is divisible into a shaft and two extremities, proximal ana distal. The shaft, which is triangular, is massive in the first, slender and much compressed laterally in the second, third, and fourth, and compressed from above downwards in the fifth. Each shaft, except that of the first, is longitudinally convex on its dorsal aspect, and they are all longitudinally concave on their plantar aspects. The shaft presents three borders and three surfaces. In the outer four bones the borders are two lateral, and a plantar. The outer borders , lateral and medial, extend from the side of the proximal end or base, close to the dorsal aspect, to the dorsal tubercle on either side of the distal end or head, and their outline is sharp. The plantar border, round behind, but sharp in front, extends from the centre of the plantar aspect of the base forwards in the middle line to near the head, where it bifurcates, the divisions passing to the condyles on the plantar aspect cf the head. The dorsal surface lies between the lateral and medial borders, and is narrow. Each lateral surface is situated between the lateral and plantar borders. The lateral surfaces, which are extensive and sloped, bound the interosseous spaces, and give attachment to the interosseous muscles. In distinguishing a metatarsal from a metacarpal bone it is very important to notice that the former has a constricted neck which contrasts very markedly with the broad triangular surface on the dorsum of the metacarpal. The shaft of the first metatarsal is prismatic. The dorsal surface is convex, and is directed upwards and inwards. The plantar surface is concave, and is in contact with the tendon of the flexor longus and the flexor hallucis brevis. The lateral surface , which is practically vertical, is narrow in front, but wide behind.
The heads of the four outer metatarsal bones are much compressed laterally, thus contrasting sharply with the metacarpals. The cartilage is prolonged more on the plantar than on the dorsal aspect, and in the former situation it ends in a concave border, surmounted at either side by a prominent condyle. On either side the head presents i dorsal tubercle and plantar depression for the plantar metatarsophalangeal joint. The head of the first metatarsal is of large size, and elongated transversely. On its plantar aspect it presents two wellmarked grooves, separated by a median antero-posterior ridge, for the sesamoid bones in the insertion of the flexor hallucis brevis.
The bases of the metatarsal bones articulate with the tarsus and with each other, except, as a rule, in the case of the first, and they present distinctive characters in each case.
First Metatarsal Bone. —This supports the great toe, and is the thickest and most massive of the series. The base is of large size, md presents a concave reniform surface, with the concavity outwards, for the medial cuneiform. Inferiorly is a projection, called the tuber3 sity, which gives insertion, by its outer aspect, to the principal part }f the tendon of the peroneus longus, and by its inner aspect to a slip the tendon of the tibialis anterior. There is usually no facet on its miter surface, but sometimes there may be one for the second metaLarsal, and it always gives origin to the inner head of the first dorsal nterosseous.
Articulations. — Posteriorly with the medial cuneiform, and sometimes laterally with the second metatarsal; anteriorly with the proximal
phalanx of the great toe; and inferiorly with the two sesamoid bones.
Fig. 239.—The First Right Metatarsal Bone (Plantar View).
Fig. 240.—The Second Right Metatarsal Bone. A, lateral aspect; B, medial aspect.
Second Metatarsal Bone. —The base of this bone is wedge-shaped, with the broad end upwards. It recedes between the medial and lateral cuneiform bones, and posteriorly presents a triangular facet for the intermediate cuneiform. On the inner side, close to the dorsal aspect, there is a small facet for the medial cuneiform, and sometimes there is an additional facet, below and in front of this, for the first metatarsal. The outer side presents two facets, dorsal and plantar, separated by a rough antero-posterior groove, each of these being subdivided by a vertical ridge into two semi-oval facets. There are thus four facets in all—a posterior pair for the inner side of the lateral cuneiform, and an anterior pair for the inner side of the base of the third metatarsal. The plantar surface of the base gives insertion to a slip of the tendon of the tibialis posterior. The shaft gives partial origin to the first and second dorsal interossei.
Fig. 241. — The Third Right Metatarsal Bone. A, lateral aspect; B, medial aspect.
Articulations. —Posteriorly with the intermediate cuneiform, medially with the medial cuneiform, and sometimes with the first metatarsal, laterally with the lateral cuneiform and third metatarsal, and anteriorly with the proximal phalanx of the second toe.
Third Metatarsal Bone. —The base of this bone resembles that of the second, the broad end being upwards. Posteriorly there is a triangular facet for the lateral cuneiform. The inner side of the base has two semi-oval facets, dorsal and plantar, separated by a rough mtero-posterior groove, for the anterior pair of facets on the outer side of the base of the second metatarsal. On the outer side there is a large oval facet, dorsally placed, for the inner side of the base of tf fourth metatarsal. The plantar surface of the base gives insertion 1 a slip of the tendon of the tibialis posterior, and origin to a portio of the oblique head of adductor hallucis. The shaft gives origin t the first plantar interosseous, and partial origin to the second and thir dorsal interosseous muscles.
Articulations. — Posteriorly with the lateral cuneiform, medially wit the second metatarsal, laterally with the fourth metatarsal, an anteriorly with the proximal phalanx of the third toe.
Fourth Metatarsal Bone. —The base is quadrilateral, and is some what broader above than below. Posteriorly it presents a quadr lateral facet for the cuboid. On the inner side there is a large ow facet for the third metatarsal, and this is sometimes prolonged to th
Fig. 242. — The Fourth Right Metatarsal Bone. A, lateral aspect; B, medial aspect.
T tf T °i f ! he , baS6 ’ - thus formin g an additional facet for the out
W aV® f te T cu , ne r lform - . On the outer side there is a large o\
tarsal Th T ^ f or * nner side of the base of the fifth met
of thphacp C ° W - ^ 1S ? ere 1S a d. ee P rough groove. The plantar surfa
and oriVin f 1Ves ms ^ rtlon to a slip of the tendon of the tibialis post eric
shaft S n a . po 5 t1 ^ of the oblique head of adductor hallucis. T
to the third ° secon< ^ plantar interosseous, and partial orig
to the third and fourth dorsal interossei.
metatarsif 10n f* ’^°fteviwly with the cuboid, medially with the thi:
fifth meth^ S ° me A lmeS With the lateral cuneiform, laterally with t] fourth toe ’ an< ^ an t enor ly with the proximal phalanx of t]
elon^ted^ronTT 1 ® one ;T This su PP°rts the little toe. The base
e o S1 de, and compressed from above downward
Medial Surface Nutrient Foramen..
[ts leading characteristic is a stout, mammillary process, situated on ts outer aspect, called the tuberosity, which is directed outwards and Dackwards, and gives insertion to the tendon of the peroneus brevis, rhe posterior surface presents a triangular facet, vith its apex outwards, for
he cuboid, the plane of vhich is inclined inwards md forwards. This facet ioes not encroach upon
he tuberosity. The inner surface presents a large Dval facet for the outer side of the base of the 'ourth metatarsal. The iorsal surface, which is rough and slightly convex,
ives insertion, as a rule, o the tendon of the peroleus tertius. The plantar F surface, which is rough md concave, gives origin
o the flexor digiti minimi. The shaft gives origin to the third plantar nterosseous, and partial origin to the fourth dorsal interosseous.
In practice it is sometimes quite difficult to determine the dorsal
rom the plantar aspect of this bone, especially when the condyles ire damaged, and it is useful to notice that on its plantar surface, near
For 4th Metatarsal
For Peroneus Tertius
Tuberosity for Peroneus Brevis
-The Fifth Right Metatarsal Bone
For Intermediate Cuneiform
For Lateral Cuneiform
Fig. 244.—The Bases of the Right Metatarsal Bones
he base, is a longitudinal depression for the flexor digiti minimi, while he dorsal surface is comparatively flat. Articulations. —Posteriorly with the cuboid, medially with the fourth metatarsal, and anteriorly with the proximal phalanx of the little toe. Each metatarsal bone has a nutrient foramen, that of the first
and second, and usually that of the third and fourth, being situatec on the outer side of each shaft, whilst that of the fifth is situated 01 the inner side.* The foramen of the first and the canal to which i leads are directed towards the head or distal end, but that of each 0 the other four is directed towards the base or proximal end.
Varieties. —(1) The tuberosity on the outer side of the base of the fiftl metatarsal, or the tuberosity on the plantar surface of the base of the first may form a separate ossicle. (2) An additional ossicle is sometimes met witl between the bases of the first and second metatarsals.
dhe metatarsus as a whole is convex on its dorsal aspect from side to side, and also longitudinally. The transverse convexity is due tc the broad ends of the bases of the second, third, and fourth metatarsah being directed upwards. On its plantar aspect it is concave from side to side, and also longitudinally. All five bones are nearly paralle' with each other, being slightly divergent in front. The interosseous spaces are as in the hand, the first being the innermost.
The phalanges are fourteen in number—three to each of the fom outer toes, and two to the great toe. The toes, from within outwards
are called great toe or hallux, second, third, fourth and fifth or little toe. In their general character* the phalanges closely resemble those of the hand but for medico-legal purposes it may be very important to distinguish them. The phalanges of the hallux are so large that there is not the least likelihood of mistaking them for those of the other toes but. there is sometimes the greatest difficulty in distinguishing those of a large man's thumb from those of a small woman s big toe. One point to be noticed is that the big toe always slants outwards towards the other toes, and the bases of both the proximal and distal phalanges are therefore oblique, thus enabling the side to which they belong to be distinguished without difficulty. This obliquity of the hallux was formerly ascribed to the pressure of pointed boots until it was noticed that in savage races, to whom boots are unknown, the same obliquity exists. Another difference is that although the length of the thumb and big toe phalanges is the same, the breadth of the articular ends of the atter is greater in proportion to the length than in
73 th°d metatarsals I ha ( ? 1 ti l e< ^ Ua + I ! un ? b ? r of fourth, metatarsal bones examined, Lnef Sid? and 60 eT* 6 ? f ? ra f! en on the outer side, and 27 on the
inner side.’ metatarsals had it on the outer side, and 40 on the
Fig. 245.—The Phalanges of the Second Toe (Plantar View).
he former. A final point is that the terminal phalanx of the big toe s always very rough and irregular on each side of the base.
In the case of the phalanges of the four outer toes the proximal md middle may be distinguished from those of the hand by the absence >f the ridges for tendon sheaths and by the lateral compression of the hafts of the proximal row, while the terminal phalanges of the foot .re hardly longer than they are broad.
Special Muscular Attachments. —The base of the proximal phalanx of the peat t°e, which presents a tubercular enlargement at either side, gives insertion nedially to the abductor hallucis and inner head of the flexor hallucis brevis * xternally, to the outer head of the flexor hallucis brevis, oblique and transverse leads of adductor hallucis,' and on its dorsal surface there is a rough transverse idge for the innermost tendon of the extensor digitorum brevis. The base of he ungual phalanx of the great toe gives insertion, on its dorsal surface, to the xtensor hallucis longus, and, on its plantar surface, to the flexor hallucis longus
Appears in the ioth Year, and joins at 16
Appears at 6th Month (intra-uterine)
9th Month (intra-uterine) 1st Year/-.
7th Month (intra-uterine).
4th Year 4th Year 3rd Year
Appears between 4th and 8th Year and joins about 19
9th Week (intra-uterine)
Appears between 4th and 8th Year and joins about 19 1 Same as for Metatarsals
.. Epiphysis _ Primary Centre
Fig. 246. —Ossification of the Bones of the Foot.
he base of the proximal phalanx of the second toe gives partial insertion edially to the first dorsal interosseous, and laterally to the second dorsal terosseous. The base of the proximal phalanx of the third toe gives partial sertion medially to the first plantar interosseous, and laterally to the third irsal interosseous. The base of the proximal phalanx of the fourth toe gives irtial insertion medially to the second plantar interosseous, and laterally to Le fourth dorsal interosseous. The base of the proximal phalanx of the fifth »e gives partial insertion medially to the third plantar interosseous and laterally sertion to the abductor digiti minimi and flexor digiti minimi. The second a a Phalanges of each of the four outer toes give insertion to extensor id flexor tendons, as in the case of the corresponding bones of the four inner igers.
The nutrient foramen and the canal to which it leads are, in each talanx, directed towards the distal end.
Varieties. — Ankylosis of the distal and second phalanges of the fifth toe of frequent occurrence, and may even involve those of other toes, up to and including the second. This process may be regarded as a stage in the evoli tion of a foot in which the three phalanges are being replaced by two.. It mus however, be borne in mind that the boot is probably the mechanical fact( of the change.
Sesamoid Bones. —These are two in number, and are of large sizi They are associated with the two heads of insertion of the flexc hallucis brevis, and lie on the plantar aspect of the head of the fin metatarsal bone. The inner is the larger of the two bones, and th saddle shape of their articular surfaces should prevent their -bein mistaken for ill-marked pisiform bones.
Ossification of Metatarsal Bones and Phalanges. —Each bone ossifies i cartilage from one primary, and one secondary, centre, which closely agree wit those of the corresponding bones of the hand in their disposition. The primal centres for the shafts appear about the ninth week of intra-uterine life, whit the secondary centres appear between the fourth and eighth year. Each ep physis joins its shaft about the eighteenth to nineteenth year, in women son two to three years earlier.
The Foot as a Whole
The foot presents two surfaces, dorsal and plantar; two border: inner and outer; and two extremities, anterior and posterior.
The dorsal or superior surface is arched, both longitudinally an transversely, and the superior surface of the talus constitutes its summii The talus is the only bone of the tarsus which articulates with th tibia and fibula.
The plantar surface is concave, both longitudinally and transversel} in conformity with the longitudinal and transverse arches. When a articulated foot is placed upon a table, with the plantar surface dowr wards, the parts in contact with the table are as follows: Posteriorly the medial and lateral tubercles on the plantar aspect of the calcanea tuberosity, and anteriorly the heads of the metatarsal bones.
The plantar surface presents important projections and groove: which will be enumerated, as nearly as possible, in order from behin forwards.
1. The medial and lateral tubercles on the plantar aspect of th calcaneal tuberosity.
The medial tubercle gives attachment to the following structures:
(1) Medial division of plantar aponeurosis (part of).
(2) Central division of plantar aponeurosis.
(3) Outer head of abductor hallucis (part of).
(4) Flexor digitorum brevis (part of).
(5) Abductor digiti minimi (part of).
The lateral tubercle gives attachment to the following structures:
( T ) Outer division of plantar aponeurosis. j
(2) Abductor digiti minimi (part of).
2. The anterior tubercle of the calcaneum , which gives attachme: to the short plantar ligament.
3. The sustentaculum tali of the calcaneum, close to the inner bord of the foot, which is grooved inferiorly for the tendon of the flex hallucis longus, the groove being continuous with that on the poster! border of the talus. Anteriorly , the sustentaculum tali gives attac ment to the plantar calcaneo-navicular ligament.
4. The tuberosity of the navicular bone , close to the inner bord< of the foot, which gives insertion to the principal portion of the tendc of the tibialis posterior.
5. The ligamentous tubercle on the plantar surface of the naviculi bone , for the plantar calcaneo-navicular ligament.
6. The eminence on the plantar surface of the medial cuneifon bone, close to the inner border of the foot, for a slip of the tendon ( the tibialis posterior.
7. The peroneal tubercle on the outer surface of the calcaneun above which is the groove for the peroneus brevis, whilst that for tli peroneus longus is below it.
8. The peroneal notch and groove on the outer border and planta surface of the cuboid bone for the tendon of the peroneus longus. Th ridge behind the groove gives attachment to the long plantar ligameni
9. The tuberosity on the plantar aspect of the proximal end 0 base of the first metatarsal bone, which gives insertion medially t a slip of the tendon of the tibialis anterior, and laterally to the mai: part of the tendon of the peroneus longus. (A slip of the latter tendo; is inserted into the lower and anterior part of the lateral surface of th medial cuneiform bone.)
The inner or tibial border of the foot is in line with the great toe or hallux. It is constructed by the calcaneum, talus, navicular, media cuneiform, and first metatarsal, and the phalanges of the great toe.
the sustentaculum tali of the calcaneum, the tuberosity of th navicular bone, and the eminence on the plantar surface of the media cuneiform bone, belong to this border.
The medial surface of the medial cuneiform bone presents an obliqu< groove, directed downwards and forwards, for the tendon of the tibiali: anterior, the principal part of which is inserted into an impressioi at the lower and posterior part of the groove.
The outer or fibular border of the foot is in line with the little toe It is constructed by the calcaneum, cuboid, fifth metatarsal, and th( phalanges of the little toe. Its markings, enumerated from behinc forwards, are as follows:
1 .^bercle for the middle fasciculus of the lateral ligament oi
the ankle-joint, situated about the centre of the outer surface of the calcaneum.
2 * P©roneal tubercle, situated a little below and anterior to the preceding tubercle, and lying between two grooves. The upper groove ransmits the tendon of the peroneus brevis, and the lower groove ransmits the tendon of the peroneus longus, whilst the ridge gives attachment to the fibrous septum, which separates the two peroneal sheaths.
Fig. 248. The Right Foot (Plantar Surface).
3. The peroneal notch, situated on the outer border of the cuboid bone, and leading to the peroneal groove, on the plantar surface of the bone, for the tendon of the peroneus longus.
4. The tuberosity on the outer side of the proximal end or base of the fifth metatarsal bone, which gives insertion to the tendon of the peroneus brevis. (The peroneus tertius is usually inserted into the dorsal surface of the base of this metatarsal bone.)
The anterior extremity of the foot is formed by the distal or ungual phalanges.
It is to be noted that the great toe or hallux is almost as long as, and parallel to, the second toe, in which respect it presents a striking contrast to the thumb or pollex. This, as well as its massive structure, is evidently an adaptation to the erect position, and the inward direction of the neck of the talus throws the weight of the body largely on to the big toe.
Fig. 249. — Scheme of a Generalized Tarsus.
The posterior extremity of the foot is formed by the calcaneal tuberosity. Posteriorly this tuberosity presents three transverse zones —upper, for a synovial bursa; middle, for the insertion of the tendo calcaneus (Achillis); and lower, for the fat of the heel.
I he posterior border of the talus, though it stops short of the posterior extremity of the foot, may be referred to. The markings which it presents are a groove and two tubercles. The groove, which is directed downwards and inwards, transmits the tendon of the flexor hallucis longus, and leads to the groove on the under aspect of the sustentaculum tali of the calcaneum. The posterior tubercle, of large size, gives attachment superiorly to the posterior fasciculus of the lateral ligament of the ankle-joint. The medial tubercle, which is small, gives attachment medially to a few fibres of the medial or deltoid ligament of the anklejoint.
The sinus tarsi or tarsal tunnel is the oblique canal which lies between the talus and the calcaneum. Its direction is outwards and forwards, and it is occupied by a strong interosseous ligament, within which is the bursa sinus tarsi.
For the arches of the foot, see p. 672.
The foot is regarded as being built up by the fusion of elements in a generalzed tarsus, the scheme of which is the same as that of the generalized carpus (Fig. 202, p. 322), the tibia taking the place of the radius and the fibula that }f the ulna.
The talus represents the tibiale, and its posterior tubercle (os trigonum) lS regarded as the intermedium. The fibulare is the calcaneum, while its posterior epiphysis may be the fibulare marginale. The navicular is obviously formed Dy the fusion of the two centralia, while the three tibial distalia remain as the cuneiform bones, and the two on the fibular side coalesce to make the cuboid. In this way only the tibiale marginale remains unaccounted for, the fate of which is uncertain.