Paper - Some factors influencing the position of the small intestine (1915)
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Crymble PT. Some factors influencing the position of the small intestine. (1915) J Anat. Physiol. 49(2): 216-352. PMID 17233027
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Some Factors Influencing the Position of the Small Intestine
By P. T. Crymble,
Lecturer on Applied Anatomy, Queen’s University, Belfast.
- Read before the Anatomical Society of Great Britain and Ireland at the Middlesex Hospital, 6th March 1914.
A number of investigators (Henke,1 Sernoff,2 Weinberg3 Mall4) have recorded observations on the position of the jejuno-ileum. They have drawn their conclusions from normal abdomens, and do not discuss the factors which may influence the position of the small intestine or may account for the various abnormal arrangements of jejuno-ileum which one frequently observes. In this paper conclusions have been drawn from all the material examined, whether normal or abnormal, and an attempt has been made to give reasons for the different arrangements.
Mall is the most frequently quoted observer, and his figures are reproduced in many of the text-books. He examined fifty adults, and forty-one of these were free from peritoneal adhesions and abdominal disease. In thirty-five of these forty-one bodies the jejuno-ileum entered into each of the three main divisions of the lower abdomen, i.e. the right and left iliolumbar regions and the pelvic cavity.
Addison5 noted the arrangement of coils, and found the upper third of the jejuno-ileum arranged in horizontal loops in 60 per cent. and the lower third of the jejuno-ileum arranged in vertical loops in 50 per cent. The reason of this arrangement is not discussed.
1 Henke, Archiv fiir Anatomie, 1891.
2 Sernoff, Internat. Monatsch. fiir Anat. und Phys., 1894.
3 Weinberg, Internat. Monatsch. fiir Anat. und Phys., 1896.
4 Mall, Retchert’s Archiv, 1897.
5 Addison, Journ, of Anat. and Phys., vol. xxxv.
Method and Material Used in this Investigation
Fifty-six adult human bodies, hardened by injection of formalin, have been examined.
Six of these were frozen for eight days and cut into sections by a hand saw.
In the cases of a girl aged fourteen years, a girl aged twenty years, and a man aged fifty years the sections were horizontal and each slab was made one inch thick.
In two bodies the sections were made by coronal saw cuts, and in the sixth body sagittal sections were made.
The remaining fifty bodies were dissecting-room subjects, very well hardened by formalin injection and immersion in formalin tanks for six to twelve months before being subjected to dissection. In these bodies the abdomen was opened by a crucial incision, and the lower ribs on the left side removed by saw cuts. A sketch of the small intestine was then made on a prepared diagram showing the bony framework and the inner margins of the psoas muscles.
In most cases the course of the small intestine in the pelvic cavity was too complicated to record.
On a second similar diagram the large intestine, liver, stomach, and bladder were sketched.
The Normal Position of the Jejuno-Ileum
The peritoneal cavity may be subdivided into four main regions :—
1. The subphrenic region, or that part lying superior to the transverse mesocolon.
2. The right ilio-lumbar region—a space, triangular in outline, bounded superiorly by the transverse mesocolon, laterally by the lateral abdominal wall, and medianly by the mesentery of the jejuno-ileum and by the right psoas margin. 3. The left ilio-lumbar region—bounded superiorly by the transverse mesocolon and the phrenico-colic ligament, laterally by the lateral abdominal wall, medianly by the jejuno-ileum mesentery, and inferiorly by the left psoas margin and the sacral promontory. It is more extensive than the right ilio-lumbar region, since it extends superiorly to a greater extent and is broader inferiorly.
4. The pelvic region—separated from the ilio-lumbar regions by the sacral promontory and the inner margins of the two psoas muscles.
Of the fifty-six bodies examined only nineteen were free from bladder or stomach distension, enteroptosis, or peritoneal abnormalities.
In six of the nineteen the jejuno-ileum was confined to the left iliolumbar and pelvic regions, and in the remaining thirteen the small intestine was distributed over both ilio-lumbar regions and the pelvic region. The amount of small intestine entering the right ilio-lumbar region was, as a rule, much less than that entering the other two regions,
Fig, 1. — Shows the six arrangements of jejuno-ileum found in an examination of fifty-six bodies. Each diagram shows the course of the ilio-lumbar smal] intestine. The course of the pelvic small intestine is too complicated to figure. The costal margin, mid-line, umbilicus, sacral promontory, inner margin of psoas, the inguinal ligaments, and the pubic crests are shown. The figures at the top left-hand corner of each diagram indicate the number of times the arrangement occurred. ABN. followed by a figure indicates the number of times a disturbing factor was present. .g., enteroptosis, distended bladder, or abnormal peritoneal fold. It will be noticed that all the cases in groups III, IV, V, and VI were associated with some disturbing factor.
Below group VI is a drawing of a horizontal] section which shows the marked increase in the size of the left ilio-lumbar region in a case of lateral curvature, convex to the right.
In twenty-six bodies the small intestine entered both ilio-lumbar regions and the pelvic cavity, and of these twenty-six the following may be recorded :—
Male aged forty-two years: One loop of jejuno-ileum in the iliac fossa below the cecum. L.LL. (left ilio-lumbar region) . 1-55 inches. R.LL. (right ilio-lumbar region) and P. (pelvis) . 56-79 ,, Pelvic mesocolon laden with fat. Large space above the bladder (probably the bladder had been previously distended with urine). Male aged sixty years, body 9: Distension of the small intestine due to a colic stricture Czecum and ascending colon covered by small intestine.
Male aged sixty years, body 2:
LIL. . : . . . . . 1-77 and 96-132 inches. ° P.. . . . . . . oo. . . 78-95 ,, RIL. . . . 132-184 ,,
Pelvic cavity ‘diminished in size by a deposit of extra-peritoneal fat and contained a partially distended and long pelvic colon.
Female aged twenty: eight years:
LIL. . . . . . 1-26 inches. P.. . . . . . . . . . 27-46 ,, R. IL, L . . . . 47-110 ,,
Much extra-peritoneal fat in the pelvic cavity. Massive pelvic mesocolon
and large appendices epiploice. Male aged thirty-nine years:
Several inches of the small intestine in the median part of the right iliac fossa.
Fundus of the cecum fixed in an inverted position by a parieto-cecal fold. Male aged thirty-one years :
Pelvic cavity occupied by a dilated pelvic colon and contained only a few inches of small intestine. Czcum and colon very contracted. Valvula coli above the intertubercular plane.
Female aged twenty-seven years :
Low attachment of the transverse mesocolon, the splenic flexure being on the iliac crest.
Male aged forty-eight years :
Pelvic cavity occupied chiefly by the distended pelvic colon and a large hard bladder.
Female aged seventy years:
One loop in a lateral paracecal fossa, the remainder of the small intestine
being confined to the left ilio-lumbar and pelvic regions. Male aged forty-nine years :
LIL. . . . . : . . . . 1-18 inches,
RIL. . . . . . 31-48 ,,
P. Remainder of small intestine.
Total length of small intestine 158 inches.
Left ilio-lumbar region chiefly occupied by the transverse colon.
In a male (body 28, 1912-13):
1-53 inches, with the exception of one loop crossing the right psoas, lay in
the left ilio-lumbar region. ‘The remainder lay in the pelvic cavity.
In many of the above cases there is a definite cause for the presence of a considerable quantity of small intestine in the right ilio-lumbar region. In some only a few inches have entered the space.
Abnormal Positions of Jejuno-Ileum
1. The small intestine is excluded from the pelvis, and is confined to the ilio-lumbar regions. Present in five. Causes :— ;
(a) Female aged thirty years. Pelvic cavity occupied by a distended rectum and pelvic colon. A large amount of extra-peritoneal fat diminished the size of the pelvic peritoneal cavity.
(b) Male aged sixty-eight years and a female aged sixty-eight years. Distension of the bladder.
(c) Male aged seventy-five years. Great distension of the rectum.
(d) Female aged sixty-nine years. Pelvic cavity occupied by the uterus, a distended rectum, and the pelvic colon.
2. The small intestine is confined to the right ilio-lumbar and pelvic regions, or a few inches only are admitted to the left ilio-lumbar region. Present in seven.
(a) The distal third or fourth of the transverse colon is fixed to the posterior abdominal wall by an abnormal peritoneal membrane. Present in three cases, 1.e. a female aged sixty-one years, a female aged sixty-five years, and a female aged eighty years (see figs. 2 and 3 and 21).
(b) Enteroptosis. Present in two cases, i.e. a female aged seventy-six years (see figs. 4 and 5) and a female aged thirty-five years.
(c) Left ilio-lumbar region occupied by a distended ascending limb of the transverse colon and a distended descending colon. Present in a female aged thirty-nine years.
(d) Left ilio-lumbar region occupied by the cecum, a large part of the transverse colon, and the first eight inches of jejunum. Present in a male aged seventy-two years.
3. The small intestine enters the subphrenic region. Present in four.
Causes :— (a) Distension of the bladder. Present in a man aged forty-three years. Left ilio-lumbar region . . . 1-89 inches.
Right ilio-lumbar and subphrenic regions . 90-172 __,, Some coils of ileum passed upwards in front of the transverse colon, and lay in contact with the right lobe of the liver.
Fig. 2. — Abnormal arrangement of peritoneum,
The tranverse colon forms a long \Yshaped loop, the apex of which lies in the pelvis. The distal third of the transverse colon is adherent to the posterior abdominal wall. This arrangement of colon prevented the entrance of small intestine into the left ilio-lumbar region, and resulted in the cecum and ascending colon being covered by smal] intestine.
Fig. 3. — Abnormal position of smal] intestine. Shows the arrangement of the small intestine in the right ilio-lumbar region of the case illustrated in fig. 2. The small intestine occupied the right iliolumbar and pelvic regions. The pelvic loops were too complicated to figure. There was no small intestine in the left ilio-lumbar region.
Fig. 4. — Female aged seventy-six years. Marked enteroptosis. The colon -was filled by scybalous masses. Right parietocolic fold, behind which was a loop of small intestine. The main mass of the ilio-lumbar small intestine lay between the ascending and transverse colons, Owing to the left ilio-lumbar region being occupied by a stomach distended and low in position, and by a colon laden with scybala, only two inches of small intestine lay in that region.
Fig. 5. — Course of the ilio-lumbar small in testine in the female aged seventy-six years, illustrated in fig. 4. Marked enteroptosis, the valvula coli lying at the bottom of the pelvis, Only two inches of small intestine lay in the left ilio-lumbar region.
Fig. 6. — Abdominal viscera of a male aged sixty-four years, viewed from the front. The urinary
bladder is distended and entirely fills the pelvic cavity. The cecum and transverse colon are enormously distended with soft feces. The descending and iliac colon, concealed from view by transverse colon and coils of small intestine, are slightly larger than normal. The pelvic colon forms a (]-shaped loop, directed upwards and to the right. The apex of this loop and some coils of small intestine are seen lying in front of the liver. They intervened between the liver and the ribs, occupying the right anterior intraperitoneal subphrenic space. This abnormal arrangement of small intestine was due to three factcrs: (a) the distension of the bladder ; (5) the distension of the cecum, ascending and transverse colons ; (c) the fixation of the distal five inches of transverse colon to the posterior abdominal wall (see fig. 7).
Fig. 7. — Abdominal viscera of a male aged sixty-four years, viewed from the left side. The anterior abdominal wall and portions of the lower four ribs on the left side have been removed. Portions of large and small intestine are exposed. The transverse colon, distended with soft feces, is attached in the terminal part of its course, for a distance of five inches, to the posterior abdominal wall by a peritoneal fold. This fold is attached, posteriorly, median to the descending cclon and has produced a marked kink at the left colic flexure (O.T. splenic flexure). t has also prevented jejunum from entering the upper part of the left ilio-lumbar region.
(6) Distended bladder and fixation of the distal five inches of the transverse colon to the left posterior abdominal wall (see figs. 6 and 7). Present in a male aged sixty-four years. Coils of small intestine lay in the right anterior intraperitoneal subphrenic space.
(c) Adhesion between the transverse colon and the left lateral abdominal wall. Present in a female aged seventy-four years. The sinall intestine was arranged thus :—
Left ilio-lumbar region . . . 1-5 and 75-91 inches.
Right ilio-lumbar region and right anterior intraperitoneal subphrenic space . . . 6-75 ,,
Pelvic region . . . remainder.
(d) Abnormal arrangement of the peritoneum with a free communication between the gastric recess of the lesser sac and the iliolumbar region. Present in a female aged sixty-five years, in whom the gastric recess was filled by coils of small intestine. A study of fig. 8 will show that the transverse colon passes below the root of the mesentery and behind the coils of small intestine, and is fixed in this position by adhesion to the posterior abdominal wall. The upper region of the abdomen is completely shut off from the lower region by a peritoneal membrane attaching the proximal fourth of the transverse colon and the great curvature of the stomach to the anterior abdominal wall, and the peritoneal cavity of this lower region passes freely upwards behind the stomach, where it is separated from the bursa omenti minoris by a complete septum bursarum composed of gastrophrenic and gastro-pancreatic folds.
The bursa omenti minoris and the peritoneal cavity in relation to the liver are normal. A gastro-splenic ligament is present, but it has no connexion with the peritoneal diaphragm above described, and it shows a free lower border.
There are two possible explanations of this condition :—
(1) That the colon rotation has not taken place in the usual manner, and adhesion between the transverse colon and the posterior wall of the lesser sac has been prevented by the coils of small intestine. The lower part of the lesser sac has been invaginated into the gastric recess,
(2) The small intestine has burst through the transverse mesocolon, entered the lesser sac, and then burst through the great omentum, thus forming a free communication between the great sac and the gastric recess. 4, The small intestine is confined to the left ilio-lumbar region.
Present in one.
This was a case of spinal curvature in a female aged sixty years. The spine was laterally curved, convex to the right, so that the dorso-lumbar region of the spine lay considerably to the right of the mid-line. There was a very marked increase in the size of the left ilio-lumbar region and a corresponding decrease in the size of the right ilio-lumbar region. The jejuno-ileum was arranged in transverse loops and only passed out of the left ilio-lumbar region to join the colon (see fig. 1 (vi)).
Fig. 8. — Abnormmal arrangement of peritoneum and transverse colon. The transverse colon passed below the root of the mesentery and behind the jejuno-ileum. Throughout its whole course it was closely adherent to the posterior abdominal walls or to viscera lying on the posterior abdominal wall. The left ilio-lumbar region communicates freely with a retro-gastric space. The smal] intestine occupied the retro-gastric space, the left ilio-lumbar region, and the pelvic cavity.
Factors Influencing the Position of the Small Intestine
1. In the Right Ilio-lumbar Region.—Normally the czecum, ascending colon, and the proximal third or half of the transverse colon are dilated and are capable of almost entirely filling the right ilio-lumbar region.
If the first part of the transverse colon descends parallel and median to the ascending colon, the probability of small intestine entering this region will be still less.
In nineteen of the fifty-six bodies the small intestine did not enter this region, and in six of these thirteen there was no abnormality, but the space was fully occupied by the distended cecum and colon. In five of the remainder there was distinct enteroptosis, e.g. :—
Male aged sixty-eight years—liver in the right iliac fossa, horizontal part of the duodenum lies below the bifurcation of the aorta.
Fig. 9. — Sketch of the colon in a female aged Frc. 10.—Course of the right and left iliothirty-one years, The first part of the lumbar smal] intestine in the female aged transverse colon is distended and overlies thirty-one years, illustrated in fig. 9. the ascending colon. The remaining part Ninety-five inches of small intestine lay of the transverse colon is much contracted. in the left ilio-lumbar region, the remain ing fifty-two inches of small intestine, with the exception of one loop, lay in the pelvis.
The right ilio-lumbar region was occupied by distended colon (see fig. 9) and admitted only a few inches of small intestine.
Female aged eighty years—ptosis of colon and colic flexures.
In the remaining two the colon occupied an abnormal position, a large part being tixed in the right ilio-lumbar region (see figs. 11 and 12).
There are two areas in the right ilio-lumbar region frequently occupied by small intestine, 2.e. the lower part of the iliac fossa and the space between the cecum and the transverse colon. Small intestine enters the former where the cecum is small or occupies a high position (see figs. 13 and 14).
Where the small intestine is unable to enter the pelvic cavity owing to distension of the bladder, rectum, or uterus, an increased amount of it lies in the right ilio-lumbar region; and a similar condition exists if the left ilio-lunbar region is unable to admit small intestine.
Normally the czcum is in contact with the anterior abdominal wall (see fig. 16), but the jejuno-ileum insinuates itself when it is driven out of the left ilio-lumbar region (see fig. 2).
2. The Left Ilio-lumbar Region. — As a rule a large part of the jejunum lies in this region, and when no other viscus encroaches excessively it arrangement, Three well-marked angulations were present (see arrows). The limbs of a loop-shaped pelvic colon were closely united at the base of the loop.
Fig. 11.—Abnormal arrangement of the trans- Fic, 12 —Arrangement of the ilio-lumbar verse and pelvic colons. The apex of a small intestine in a male aged fifty-two loop of transverse colon was fixed to the years, in whom the transverse colon was hepatic flexure, the loop and the proxi- abnormally arranged and prevented the mal few inches of the transverse colon small intestine entering the right ilioforming a closely united triple-barrelled lumbar region (see fig. 11).
arranges itself in horizontal loops. The transverse colon lies anterior to this jejunum, and the descending colon lies posterior to it. The relation of the iliac colon is variable, being at times covered by small intéstine and at times in contact with the anterior abdominal wall.
The various conditions which prevent the entrance of small intestine into this region, 7.c. abnormal peritoneal fold, enteroptosis, dilated colon, are mentioned previously under Abnormal Positions of Small Intestine. In addition to these, one may mention three pathological conditions, viz., enlarged spleen, enlarged kidney, enlarged left lumbar lymph glands.
The last one was associated with new growths of the left testis, and the small intestine was forced into the right ilio-lumbar region. Distension of the stomach drives the small intestine from this region.
In one case (fig. 1) all the small intestine, with the exception of the pars cecalis ilei, lay in the left ilio-lumbar region and was arranged in a series of horizontal loops.
3. The Pelvic Cavity.—This contains the chief mass of the ileum.
Fig, 18. — Male aged sixty-three years. The Fic. 14.— Male aged sixty-three years. fundus of the cecum is fixed in a high Course of the right and left ilio-lumbar position by a pre-renal appendix. Kinks small intestine. A loop of ileum occupies are present in the pars cecalis ilei and at the lower part of the right iliac fossa. the hepatic flexure. The first few inches The first eighty-two inches of small inof the transverse colon descends retro- testine is seen lying in the left ilioperitoneally behind the ascending colon. lumbar region. Inches 82-178 occupied
The high position of the cecum per- the pelvis, but are not figured. The mits small intestine to enter the lower portion 178-210 re-entered the left iliopart of the right iliac fossa (see fig. 14). lumbar region and then passed down wards and to the right towards the valvula coli. Owing to the high position of the cecum, a loop of ileum was permitted to enter the lower part of the right iliac fossa.
Owing to the greater capacity of the female pelvic cavity there is usually more pelvic small intestine in the female than in the male.
The terminal portion of the ileum passes upwards and forwards from the bottom of the pelvic cavity to the valvula coli, situated in the right iliac fossa. During its course it lies against the right lateral wall of the pelvis, and as it crosses the right psoas margin it can be rolled under the palpating fingers and can be easily recognised, especially during contraction of the psoas muscle. Some Factors influencing the Position of the Small Intestine 229
In a minority of cases it passes obliquely downwards from the left ilio-lumbar region to the right iliac fossa.
Fig. 15. — Horizontal section of a girl aged fourteen years, through the dise between the second and third lumbar vertebre. The right ilio-lumbar region is chiefly occupied by transverse colon, ascending colon, and duodenum.
Fig. 16. — Horizontal section of a girl aged fourteen years, through the disc between the fourth and fifth lumbar vertebra. The cecum, as usual, fills the right iliac fossa, and is lying in contact with the anterior abdominal wall. The iliac colon is in its normal contracted condition and © is covered by small intestine.
The fixation of the pelvic colon to the left side of the pelvic cavity influences the ileum to occupy the right side of this region.
The following conditions diminish the capacity of the pelvic cavum peritonei and more or less completely prevent the ileum entering :— (a) Excessive amount of extra-per itoneal fat. (b) Distension of the bladder. (c) Distension of the rectum. (d) Enlargement of the uterus. (e) Distended pelvic colon occupying this region.
Fig. 17. — Female aged sixty-seven years, show- Fig. 18.—Sketch of the ilio-lumbar small
ing enteroptosis and a median paracolic intestine in a female aged sixty-seven fossa formed by a peritoneal membrane years (see fig. 17).
connecting the ascending and transverse colons. This fossa contained a twenty seven-inch loop of ileum.
The portion of transverse colon indi cated by dotted lines was overlain by jejunum.
4, In the Subphrenic Region.—Small intestine came in contact with the diaphragm in four of the fifty-six cases. In three of these a peritoneal abnormality accounted for the arrangement, and in the fourth case there was a distended bladder.
As a rule the small intestine is forced upwards in front of the transverse colon into contact with the right lobe of the liver and the costal margin, but in the very rare case illustrated in fig. 8 the small intestine passed upwards into the gastric recess of the lesser sac.
Arrangement of Jejunum in Left Ilio-Lumbar Region
The arrangement of the jejunum in the left ilio-lumbar region was recorded in forty-five bodies.
Fig. 19. — Reconstruction of the stomach and colon from a series of horizontal sections, through the abdomen of a girl aged twenty years. There is marked enteroptosis.
Fig. 20. — Reconstruction of the duodenum and left ilio-lumbar small intestine from a series of horizontal sections, through a girl aged twenty years. There is marked enteroptosis, and, with the exception of the few loops lying in the left ilio-lumbar region, all the jejuno-ileum lay in the pelvic cavity.
Fig. 21. — Female aged eighty years. All the jejuno-ileum lay in the pelvic cavity, except a loop lying anterior to the cecum and the first five inches of jejunum, which lay in a retro-mesocolic fossa in the left ilio-lumbar region. This fossa was bounded on the right and anteriorly by the transverse meso-colon. On the left it was bounded by an abnormal peritoneal fold which fixed the terminal fourth of the transverse colon to the posterior abdominal wall, median to the iliac and descending colons. The result of this arrangement of peritoneum is the almost complete absence of jejuno-ileum from the left ilio-lumbar region and the presence of jejunoileum in front of the cecum.
Fig, 22,—Reconstruction of the urinary bladder, the terminal portion of the ileum, the cecum, the colon, and the rectum, from a series of horizontal sections through a man aged fifty years. Rectal constrictions are well marked. The upper surface of slab 19 is seen in fig. 24.
In eleven the jejunum was arranged in horizontal loops, and all these abdomens were normal. ;
In twenty the jejunum was arranged in vertical loops; but of these twenty, fourteen showed some encroachment on the left ilio-lumbar region by either a distended stomach (ten cases) or an abnormal colon (four cases).
Fig. 23. — Reconstruction of the small intestine of a man aged fifty years. It is unusual to find the small intestine so evenly distributed between the right and left iliolumbar regions. Reference to fig. 22, where a reconstruction of the bladder and colon is illustrated, will demonstrate the factors controlling this arrangement. The descending and iliac colons are abnormally distended. The bladder occupies a large part of the pelvic cavity and is in a distended condition.
In fourteen the arrangement could not be classified owing to irregularity of the loops, and ten of these fourteen showed abnormalities, 2.e. six—no small intestine in the pelvic cavity: two—distended stomach; two— abnormal colon.
It would appear, therefore, that the upper part of the small intestine is normally arranged in horizontal loops, but that this arrangement gives place to vertical loops in the presence of any factor diminishing the left ilio-lumbar small intestine space.
In support of this conclusion it may be noted that in the case of enlargement of the left ilio-lumbar region, due to lateral curvature, the entire mass of jejuno-ileum was accommodated in this space and arranged itself in horizontal loops.
Fig. 24. — Horizontal section through the pelvis of a man aged fifty years. The fundus of a distended bladder, separated from the anterior abdominal wall by a coil of-ileum, is seen in the centre of the section. The left half of the pelvic cavity is occupied by pelvic colon. Numerous coils of ileum fill up the right half of the pelvic cavity. The level of this section in the reconstruction (fig. 22) is indicated by the arrow above the figure 19.
The interpretation of the various percussion notes obtained over the abdomen is facilitated by a clear conception of the probable position of the small intestine, ¢.g., the absence of the usual cecal note may lead the observer to the discovery of an abnormal peritoneal arrangement in the left ilio-lumbar region whereby small intestine is forced between the cecum and the anterior abdominal wall, or the loss of the cacal note may be due to distension of the small intestine.
It must be noted that the position and relations of abdominal viscera may be altered by opening the cavum peritonzi in the living person, since the intra-abdominal positive pressure will drive the mobile small intestine towards the opening.
The X-ray examination of the bismuth meal shows the jejuno-ileum bismuth as scattered dark areas, chiefly in the pelvis. No doubt in the erect position the main mass of the small intestine lies in the pelvis.
- Fifty-six adult bodies were examined.
- Six bodies were frozen and cut into sections.
- In twenty-six bodies the small intestine entered both ilio-lumbar regions and the pelvic cavity.
- In thirteen bodies the small intestine was confined to the left iliolumbar and pelvic regions.
- In five bodies the small intestine was confined to the ilio-lumbar regions.
- In seven bodies the small intestine was confined to the right iliolumbar and pelvic regions.
- In four the small intestine entered the subphrenic region.
- In one the small intestine was confined to the left ilio-lumbar region.
- In the normal abdomen the jejuno-ileum lies in the ilio-lumbar regions and the pelvie cavity, or is confined to the left ilio-lumbar region and the pelvic cavity.
- Physiological Alterations.—The pelvic small intestine is forced into the ilio-lumbar regions by distension of the bladder, rectum, or uterus. Distension of the caecum and ascending colon forces small intestine out of the right ilio-lumbar region, and distension of the stomach forces small intestine out of the left ilio-lumbar region. Small intestine lies anterior to the upper end of a distended bladder (see fig. 24).
- Anatomical Variations.—Fixation of the distal third of the transverse colon to the posterior abdominal wall confines the small intestine to the right ilio-lumbar and pelvic regions, and is associated with the presence of small intestine in front of the czecum.
- Enteroptosis is associated with the absence of small intestine from the right ilio-lumbar region. In marked enteroptosis the small intestine is almost entirely confined to the pelvic cavity (sec figs. 19 and 20).
- When there is a sufficient amount of room the jejunum tends to arrange itself in horizontally placed coils in the left ilio-lumbar region.
- The presence of small intestine in the subphrenic region is abnormal, and is associated with some peritoneal variations or excessive distension of some viscus.
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