Paper - Teratological studies (1919)
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Mark Hill (talk) 17:58, 16 August 2019 (AEST) Please note the term "monster" is the historic term for gross developmental abnormalities and is no longer used and is also offensive. It has been left within this text as this is how such major abnormalities were medically referred at that time, and I apologise for any offence to the reader that use of this term may cause.
D. A Second Anencephalic Monster. Complete Craniorrhachischisis
Eben J. Carey
Department of Anatomy, Creighton Medical College, Omaha, Nebraska
Seventeen Figures (1919)
I wish to express my sincere thanks to Drs. Alonzo Mack, J. S. Foote, T. J. Dwyer, and C. J. Nemec, for the specimens herein studied, and to Dr. A. F. Tyler, for the skiagraphs of the skeletons, and would also acknowledge the helpful interest and suggestions of Prof. H. von W. Schulte, Director of the Department of Anatomy in this school.
A. On a Phocomelus with Especial Reference to the Extremities
The term phocomelus is derived from the Greek cf) u x v, seal, and iJL k\ s, limb. The chief characteristic of monsters belonging to this class is an abnormal shortening and arrest of development of some or all of the long bones of the extremities. The feet and hands are usually composed of the normal number of skeletal elements, but generally appear to arise directly from the pelvic and shoulder-girdles, respectiveh', which lends them the fantastic appearance of a seal's flippers.
The specimen described was obtained by Doctor Mack, Professor of Obstetrics, Creighton ]\Iedical College, February, 1917. It was a full-term, still-bom fetus, and parturition was marked by excessive dystocia. The weight was 2500 grams and the crownrump measurement 25 cm. Through the shoulder and peh'ic regions it measured 12 and 10 cm., respectively.
The marked umbilical hernia, in which the coils of the intestines show through the attenuated walls at the base of the umbilical cord, is readily apparent in figure 1. This is due to arrested development. Xonnally, fi\'e or six primitive intestinal loops, by rapid elongation in embryos between 17 and 20 mm. in length, push their way into the umbilical coelom, producing the normal hernia funiculi umbilicalis physiologica, where they remain until the embryo reaches a length of between 35 and 45 mm. Soon after the latter period the intestinal loops return to the abdominal cavity proper.
The lateral contour of the abdominal and thoracic regions is exceedingly convex, depending upon the excessive size of the Uver. Normally, the liver at term is one-twentieth of the total body weight in the still-bom, Jackson ('09). The liver in this case, however, weighs 490 grams, or about one-fifth of the total body weight. The excessive size of the liver is due to two factors: first the umbiUcal hernia; second, the cleft sternum, both operating to release the liver from the confinement which is nonnally present. The liver in coelossomic monsters, like the brain in cases of hydrocephalus, shows a tendency to assume an unnatural bulk when relieved from the nonnal pressure of relational structures.
In the embryo the ventral wall of the trunk is at first very thin, and the heart with its various parts as well as the liver and other viscera may be seen through it. From the sides the anlagen of the skeleton and musculature grow into the walls: arrest of this growth may occur and produce ectopia cordis and fissura stemi. which depend ii])()ii the disturbance in the thoracic region. A portion of the intestine, as noted above, nonnally projects into the lunbihcal cord at the tune that the outward growth of the abdonimal walls occurs. Nonnally, the intestinal hernia recedes into the abdominal cavity with the further development of the abdominal walls, but if the latter are an-ested in their development, the heniia persists, as is seen in this specimen.
Fig. 1 Phocomeius. ventral view.
Fig. 2 Phooomelus, right lateral view.
Fig. 3 Phocomeius, left lateral view.
Fig. 4 Phocomeius. dorsal view.
The upper extremities are much distorted and resemble in no way, except in the contour of the shoulder and in the digits, the extremities of a nonual full-tenn fetus. The palmar surfaces of the hands are turned mesiad, a retention of the position which is nonnal in embryos of 18 to 25 mm. in length.
The median raphe extending from the anus to the scrotum is well marked. The scrotmn is composed of two fat-filled pouches which do not enclose the testicles. These organs are found in the inguinal canal about read}' to emerge at the external abdominal ring.
The lower extremities also show the degree of rotation characteristic of a normal embryo 18 to 25 nun. in length. The knees are directed ventrolateral, while the jilantar surfaces of the feet are turned mesial and consequently are opj^osed to each other. The dorsum of each foot is unusuallj' high. The abducted position of the great toe and the metatarsal pads are especially clearly seen in the right foot. This is characteristic of embrj'os of about 25 mm. in length. The metatarsal i)ads normally undergo a gradual retrogression and their outlines become indistinct during the fourth and fifth months. The phalangeal pads of the great toe, and in a less degree the second and third toes, of the right foot are clearly shown.
The right upper extremity is best seen in figure 2. The shoulder and wrist are recognizable and a slight groove dorsally in the region of the axilla marks the i)osition of the elbow. The lianb is so placed that the extensor surface is directed laterad. The five digits are distinct; the thumb is certainly i-udimentary. The hand is unusually broad toward the base of the fingers; this is another early fetal characteristic which has been retained.
In the lower extremity the heels are well marked and the foot is extended as a result of the contractm^e of the gastrocnemius muscle: this occasions the talipes equinus variety of club-foot. In addition, the foot is inserted so that the soles are opposed to each other by the contracture of the tibialis anticus muscle, resultmg in the talipes varus variety of the club-foot. This is mereh' arrested development, however, for the position described above is a normal phase of limb rotation and is regularly present in embryos of 35 mm.
The head is abnonnally large: the forehead is especially protuberant. This is partly due to arrested development and parth' to its hydrocephalic condition. The anterior and posterior fontanelles and sagittal suture gape in an abnormal manner because of the distended cerebral hemispheres. The protuberant forehead resembles the condition found in prosencephahc monsters. In addition to hydrocephalus, there is an extensive meningeal hemorrhage incident to labor.
The root of the nose is deeply depressed, and the nose as a whole is very low and broad. The upper lip projects, whereas the lower one recedes. The depression between the root of the nose and forehead is nonnal in embryos between 18 and 42 nun, in length, but later this character is effaced.
The shoulders are distincth' marked, as seen in figure 3. The protuberance due to the acromial process of the scapula is especially distinct on the left side. The disproportion between the segments of the limbs is striking. In each lower limb a dorsal groove is seen which corresponds to the popliteal space. It is at once evident (fig. 4j that the region of the thighs is gi'eatl^' shortened, and a corresponding shortening of the proximal segment of the upper limb is also apparent.
The left lateral aspect is reproduced to show the s\^mnetry of the surface abnonnalities (compare figs. 2 and 4;. Externally a tendency is detectable to subdi\'ision of the upper extremity into ann. forearm, and hands by grooves which lunit these regions. Rudiments of the finger nails may be detected, but these structures have not broken through the overlying epidennis.
In the lower extremity tlie regional outlines are not as distinct as in the upjier. The area corresponding to the knee is directed cejihalolateral, but there is no definite demarcation between the dorsum of the foot and the leg. The toe nails and toes are not a*^ well developed as the finger nails and the fingers.
The rotundity of the cheeks is quite marked (fig. 4), and welldeveloped sucking pads were found on dissection.
The symmetrical arrest of development of the lower extremities is clearly seen in figure 5.
The section of the alimentary canal, contained in the umbilical hernia, consists of the cecum, appendix, 2 cm. of the ascending colon, and 10 cm. of the ileum. The latter possesses a marked ^Meckel's diverticulum, from the apex of which a fibrous strand extends into the cord for some distance, eventually to be lost in its connective tissue. The remaining coils of the small intestine are arranged in the normal manner. Coil no. 1 forms the duodenum; the secondary derivatives of coils nos. 2 and 3 are found in the left hypochondriac region, those of coil no. 4 are found in the right hypochondriac region, while those from coil no. 5 are located in the left iliac fossa. So far the arrangement of the small intestine is normal; however, the derivatives of coil no. 6, instead of occupying the hypogastric region, extend directly to the base of the umbilical cord and enter into the umbilical hernia as noted above.
The liver is nearly three times the size of the organ normally found in still-born infants by Jackson ('09), and the spleen is nearly six times its normal weight. The kidneys and spleen are also found to be overweight. The pancreas, bladder, prostate, and testicles are about the normal size.
The heart is hypertrophied; it is about doul)le the average size. The two lungs are much compressed, being only of about onehalf the normal size. The thymus is double the average weight, whereas the thyroid is about normal. To facilitate comparison with ccMiditions in still-born infants of the tenth month, the weights of the several organs and their percentage of the total body weight are given in table 1, to which are added the findings of Jackson in his series of still-born infants.
Fig. 5 Phocon.elus. caudal view.
Fig. 6 Phocomelus, skiagraph from in front. Natural position of lin.bs.
Fig. 7 Phocomelus, skiagraph. The arms abducted to show curvature of the radii.
Fig. 8 Phocomelus. Skeleton of the upper extremity.
Relative sizes of the fetal organs of the still-born phocoiiu was compared to those in still-born infants by Jackson
Right suprarenal Left suprarenal. . Thyroid
MALE STILL-BORN TENTH MONTH (JACKSON)
71 65 80 69 69 71 70 9 9
12.91 0.296 0.69 0.9S 0.79 4.81 0.27 0.367 0.341 0.101 0.111 0.111
MALE STILL-BORN PHO COMELUS TENTH MONTH.
TOTAL WEIGHT 2500
Skeletal and muscular systems
The scapula is peculiar in that it possesses no glenoid articular cavity; in its place there is a large rounded protuberance which fits into a corresponding cartilaginous depression of the humerus. The body of the scapula is ossified, but the vertebral border, inferior angle, coracoid process, and acromion are cartilaginous.
A supraspinous muscle arises from the corresponding fossa, but no omohyoid nor levator anguli scapulae muscles are present. The trapezius and rhomboid muscles arc normally located. From the infraspinous fossa arises an infras]:)inatus and from the vertebral border the teres major and minor take origin. The fibers of the deltoid and trapezius muscles are, for the most part, directly continuous over the spine of the scapula, but there is a deep fibrous inscription which unites this complex muscle mass to the spine. There is a well-marked cartilaginous supraglenoid tubercle for the attachment of the long head of the biceps; the short head of this muscle arises in common with the coracobrachialis muscle from the joracoid process. Both heads of the biceps, the coracobrachialis and the deltoid muscles, fuse to fonn one large complex which is inserted into the radius, no fibers whatever finding attachment on the humerus. From the infra-glenoid tubercle, which is cartilaginous, arises the middle or long head of the triceps ; this is the only representative of the normal triceps muscle, the other two heads being absent.
The humerus is represented by a small, all but shapeless mass of soft cartilage. On its superior aspect it presents a deep articular cavity into which fits the head on the scapula described above. This head is finn and calcified, but no secondary ossification center is present : absolutely no calcification is found in the humeral mass. Xo doubt this difference in density" is the immediate cause for the reversal of curvature at the shoulderjoint, determining the presence of a scapular head and a humeral articular cavity. Caudal to this cavity the humerus is produced into a rounded process of cartilage surrounded by a dense mass of fibrous tissue, upon which is inserted the teres major and minor, supraspinatus and pectoraHs minor muscles. Xo brachiahs anticus muscle is present. A few fibrous strands extend from the pectorahs major and latissunus dorsi, to the dense perichondrium of the humeral mass, but the major part of the insertions of these two muscles are by tendon into the proximal end of the radius.
The common origin of the flexor group of muscles of the forearn, for the most part, is from the proximal end of the radius. There is a small direct continuity, however, on the part of the flexor muscles with the biceps by means of muscular slips. Similarly, the extensor group. arising in the main from the proximal end of the radius, has dii'ect muscular continuity with the triceps.
The radius is the largest and longest bone of the upper extremity. It is well ossified and bowed in adaptation to the abnormal stresses and strains to which it is subjected. At its upper end it presents a concavocon\ex articular surface which articulates with the lower convex surface of the humerus. The uhia does not enter into the f(^rniation of the elbow-joint and is merely a cartilaginous l)ar extending from the upper extremitj^ of the radius to the carpus.
The carpal elements, navicular, lunate, triquetral, pisiform, greater multangular, lesser multangular, capitate and hamate, are each defina)3le. They are, however, nothing but cartilaginous nodules presenting but a very faint resemblance to the normal components of the carjnis.
In the metacarpus and phalanges the nonnal nmnber of elements are present, but they are abnormally shortened, especially the metacarpals. All are in a cartilaginous state except the terminal phalanges in which ossification is beginning at the distal extremities. The proximal articular ends of these phalanges are cartilaginous.
The wrist is extended and the hand is adducted towards the ulnar side. It is interesting to note at this point that the flexor carpi ulnaris and the extensor carpi ulnaris are practically one muscle. At their origins these muscles are inseparable. The former is inserted partly- into the pisiform and partly into the ulnar side of the base of the fifth metacarpal element. The latter muscle is inserted also, on the ulnar side of the base of the fifth metacarpal element. The greater muscular mass of the extensor group combined with the physiological unity of the flexor and extensor carpi ulnaris muscles explains the extended position of the wrist and the inclination of the hand to the ulnar side.
The sternum is widely cleft, indeed, union is present only at its cephalic extremity. This point evidently represents the persistent episternal band which has become chondrified. Through this band the clavicles are in direct continuitj^ across the ventral median line. The extent of development of the thoracic walls is comparable to that of an embryo of about 17 mm. in length (Muller, '06). The sternal ends of the lower eight cartilaginous ribs do not extend medialward beyond the midaxillary line, and in this connection it is interesting to note that both the rectoabdominales are absent. It is highly probable that their development was initiated, but that subsequently they degenerated, for a rectus sheath was found on dissection containing a mass of adipose tissue. The obhque and transversalis are imperfect especially towards the thorax. The nerves of the region appear normal and have the usual course and distribution, so the defect in the skeletogenous tissue would seem to be the important factor in the development of these muscles. Towards the pehis the musculature is more nearly normal. Two small p\Tamidalis are present, extending from the pubis to the rectal sheath, and the caudal portions of the flat muscles are readily defined, but less developed than in a normal fetus at term.
Ventrally between the condyles is a smooth cartilaginous elevation attached to the femur at the site of the patellas trochlea. The inhibition of development here present would seem to be associated with the failure of limb rotation and in particular to the imperfect condition of the quadriceps extensor, which has alike failed to detach the patella and to bring the limb into normal position. The muscle is represented by a small rectus, associated with which are a few fascicuU on each side corresponding to the vastus mediahs and lateralis. With the latter the gluteus maximus is continuous. Xo traces were found of either the vastus intermedius or the subcrureus. The gluteus medias and gluteus minimus are inserted into the greater trochanter on its lateral aspect, into its ventrocephalic surface a fused muscle mass, representing the pyTiformis. obturator intemus and gemelli, is inserted.
The adductors magnus, longus, and brevis are small ; separable at their origins, they insert by a common tendon into a ridge immediately above the medial condyle. The psoas iliacus inserts into the lesser condyle: the pectineus is attached immediately distal to it. Xo popliteus nor plantaris muscles are present. The gastrocnemius is a very large mass, and no septal division of this mass is found which would reveal an underlying soleus. The former muscle arises prmiarily from the dorsal aspect of the tibia, however, a few muscular and fibrous prolongations are found attached dorsally to the distal extremity of the femur mmiediately cephalad to each condyle.
1 1 e tibi . like the rc/Uu-^ of the upper extremity, is abnormally curved, with the convexity directed ventrad, but not to such a degree as the radius. The tibial diaphysis is completely ossified, being separated from the epiphyses by intermediate zones of growing cartilage.
There is no fibula.
As a result of the persistent continuity of the patella with the femur, there is no retropatellar extension of the cavity of the kneejoint.
Into the cartilaginous knob, which represents the patella, are inserted a few fibrous bundles from the tendon of the very small rectus f em oris.
Here again emphasis should be placed on the fact that the quadrice])s extensor muscle is represented chiefly bj^ a rudimentary rectus femoris. The vastus internus and externus possess but a few muscular strands, which arise from the mesial and lateral aspects, respectively, of the greatly shortened femur. The vastus intennedius and subcrureus are absent. We have already noted the fact that the adductors, although present, are very small. Here again the normal stimulus to muscular differentiation and development is either absent entirely or minimal. All the nerves are present. The only absent element which we can discover in the thigh is the diaphysis of the femur. Evidently, then, the teratological evidence indicates that the more rapidly developing skeletal (blastemal-chondrous or osseous) axial zone is the nonnal stimulus in nmscular development, and if it is absent entirely or very much reduced, we find also retarded development in the musculature. This fact further explains the failure of separation and rudimentary condition of the patella as correlated to the inhibited development of the quadriceps extensor.
The flexor muscles of the leg form a larger mass than the extensors. This directs the convexity of the tibial bow ventrad. The large gastrocnemius inserts into the cartilaginous calcaneus. The tibialis posticus and the flexor digitorium longus are fused at their origins, but separable at their insertions. The latter muscle also gives rise to the tendon of the flexor hallucis longus, which has no independent belly.
The tibialis anticus is a large muscle and not only has its normal insertion but distributes the tendons normally belonging to the extensor longus digitoruni. These tendons, however, are small; the latter muscle is absent as well as the three peroriei muscles which nonnally find their origin on the fibula.
In the tarsus the calcaneus, astragalus, cuboid, and navicular are discrete cartilages, but the cuneiform elements form a fused mass.
The metatarsals and phalanges are represented by short, thick cartilage rods. The terminal phalanges have ossification centers at their distal ends. This is comparable to the terminal phalanges of the upper extremity (fig. 8).
The intrinsic muscles of the plantar surface of the foot were not well defined and formed a common muscle mass in which considerable fatty degeneration had taken place.
The condition of club-foot in this monster is readily understood in reference to the extent of development and contraction of the muscles; those belonging to the tibia are well developed, but the fibular muscles are absent except for some of their tendons of insertion which have become amalgamated with the tibial muscles, in consequence the latter group of muscles are practically unopposed in their action. The tibiahs anticus manifests its action by inverting, the strong gastrocnemius by extending the foot, resulting in a talipes equino varus.
In concluding this section I wish again to emphasize the fact brought out in this study, that in the complete absence or rudimentary development of a part of the skeleton, we also find a complete defect or rudimentary development of the related muscles. The converse is also true that an overdevelopment of the skeletal parts is accompanied by a greater degree of development of the related muscles.
B. The External Form of an Abnormal Human Embryo of Twenty-Three Days
This specimen was given to the writer by Dr. C. J. Nemec, Instructor in Surgery, Creighton University Medical School, January 31, 1917, three hours after miscarriage. The history of the pregnancy is as follows:
The woman, twenty-one years of age, Bohemian, had been niarried five years. She began menstruating at twelve years of age and invariably suffered from dvsmenorrhea. Leucorrhea was always evident two to four (lavs before each period. Her time was irregular; it was not unusual for her to miss a periotl completely. She had given birth previously to three sicklv children, the second of which died two months after birth. The last child was born July 31, 1917. During lactation there was the usual condition of amenorrhea. The nursing child was weaned Januarv 6, 1917. Her first coitus since the birth of her last child was on January 7, 1917. On January 25, she noticed a slight flow, the first since her last conception. This condition of metrorrhagia continued until January 31, 1917. At first she thought this was the reappearance of her normal menstruation. But, on the latter date, a hemorrhagic mass was passed, and then I was called on the case. I saw immediately that the uterine decidua had been passed and I had no difficulty in finding the chorionic sac imbedded in this bloody mass. I put the entire mass in 10 per cent formalin, within one hour after it had been expelled, when I returned to my laboratory.
The chorion was found covered with villi 2 mm. in length. The chorionic sac measured 20 x 19 x 10 mm. I opened it and found the abnonnal embryo with its neck extended contained in an amnion with the normal amount of liquor amnii. The chorion was sectioned and was found to be normal, save that it was covered with necrotic syncytium. In this syncytium there was a slight round-cell infiltration. The embryo was unbent in the cervical region obliterating the nape flexure. Especial care was taken to preserve the embryo in the exact position in which it was found. It remained in Zenker's fluid eighteen hours, and excellent preservation was obtained, the surface relief standing out prominently. *
Fig. 9 Phocomelus. Skeleton of the lower extremity.
Fig. 10 Twenty-three-day embryo. A pointer is in the amniotic cavity. Fig. 11 Twenty-three-day embryo. Fig. 12 Twentj^-three-day embryo. Fig. 13 Twenty-three-day embryo.
Chorion (above) and deciduae (below)
Ventral view. Right lateral view. Left lateral view.
Age. No approximate age in days can be computed from the menstrual history, since the woman was in a condition of amenorrhea at the time cohabitation and fertilization occurred. The former took place January 7, and the miscarriage occurred January .31. Undoubtedly, a living ovum was in the outer third of the Fallopian tube at the time of cohabitation. Allowing twentyfour hours until the time that fertilization occurred, the aborted ovum would be approximately twenty-three days old. The embryo is certainly not over one month old, as the external anatomy agrees very closely wuth the description of embryos between the twenty-first and the twonty-thinl days. The embryo stands very close to the embryo a of His's nonnentafeln; embryo 112 of Keibel's collertion. noniiontafohi of Kicbol and Elze. and embryo G 31 of the Anatomical l^iological Institute of Berhn. The specimen is younger tlian the twenty-six-day-old normal embryo described by Mall ( '91 ). In Mall's embryo the eyes are further developed, the liver swelling is more prominent, the branchial arches and clefts are more differentiated, especially the maxillary process of the mandibular arch : the nasal pits are larger, and the limb buds more extended from the body wall. The monster under consideration, however, is older than the 4 mm. embryo described by Bremer, which is estimated approximately at twenty to twenty-one days old. In Bremer's embryo there is no surface marking for the eye and no posterior limbs. The shape, size, and degree of development are midway between Bremer's 4nun. embryo, aged twenty-one days, and ^Mall's 7-mm. napebreech embryo, twenty-six days old, and twenty-three days in all probabihty is its age. The measurements of the embryo before fixation are as follows:
m m .
Height of yolk-sac when it projects fror.. ur. bilicus 0.9
Maxin al height of yolk-sac 2.5
Length of yolk-sac 4.0
Length of posterior portion of body, measured from the point of
emergence of yolk-sac 0.9
From fore-brain to tip of coccyx following curvature 13.0
Straight line from l)oundary between neck and thoracic region.'? to _
twelfth thoracic segment (nape-breech) 40.0 - . A
Greater length in a straight line (crown-breech) 6.0
From vertex to behind the m.andibular process 0.9
From vertex to behind the heart 3.3
It is readily apparent from the photographs that the cervical flexure of the embryo has been abnoniially unbent. This is further seen in the sharp groove on the nape separating the neck from the back. There is a very marked degree of curvature noticed in the dorsal, lumbar, and coccygeal segments. If the neck and head had not unbent, the embryo would fomi ahnost a complete cncle; the tail would he m close proximity to the head, if not actually touching it. The body is bent anteriorly and at the same tune sphally twisted about its axis so that the head is turned shghtly to the right and the pelvic end to the left.
The first, second, third, and fourth arches are clearly defined, especially the nodular ventral end of the mandibular arch ffig. 13). The maxillary processes are perceptible on both sides, not to the extent, howe^'er. found in ^vlall's twenty-six-day old embryo. The second bar is not so bulbous as the first nor the third so prominent as the second. The region of the sinus praecer^-icahs is distinct, but not so depressed as in flail's embryo. The fourth arches are barely perceptible on both sides. They lie deep m the groove of the sinus praecervicalis and are covered b}' the third arches. The clefts begm to show a shght irregularity. Above the branchial region (^approximateh' above the second visceral groove) on both sides there is a smaU oval depression inunediately above the otic vesicle measuring 0.25 nmi. in diameter.
The head shows the outline of the bram and the marked elevation over the region of the Gasserian ganghon. The shape of the cerebral hemisphere, the interbrain. midbrain, and afterbrain are plainly recognizable, and the boundaries of the fourth ventricle are sharply defined. From the dorsolateral aspect I was able to define the neuromeres in the lateral waUs of the fourth ventricle: these appeared as bilaterally s}inmetrical transverse folds. The optic vesicles are circular in fonn on each side and measure 0.3 mm. in diameter. The nasal pits are oval and shallow, but not as large as [Mali found them in his embryo. The mouth is a large shallow pentagonal depression bounded above b}' the nasofrontal process: below and lateral by the nodular mandibular processes on both sides: and lateral, the mmute elevations craniad to the mandibular processes, the incipient maxillary processes. It is readily apparent that a line drawn vertically through the ventral ends of the four visceral arches would be approximately straight and would cut the forebrain some distance in front of the optic ^•esicles. The marked prominence of the forebrain noticed in the phocomehc monster we see is a very characteristic human feature in earh' embrj'os.
Fig. 14 Craniorrhachischisis. Ventral view.
Fig. 15 Craniorrhachischisis. Hifiht lateral view.
Fig. 16 Craniorrhachischisis. Skiaura|)h. Dorsal view.
Fig. 17 Craniorrhachischisis. Skiagraph. Lateral view.
The anlage of the heart projected ff-om the ventral surface of the body as a large nodular swelling: its prolongation on the right side extends forward as the aortic bulb. If the neck was normally bent, the relief of the aortic bulb would extend to the edge of the mandibular arch. The atrial portion of the heart is seen as a protuberance on the lateral wall through the thin wall of the pericardial canity. The atrial swelling is more marked on the left side and the swelling of the aortic bulb on the right. Caudal to the heart the \4teUine vesicle projected from the umbilicus; this vesicle was shrunken and pear-shaped.
The liver swelling is poorly developed and the tail is curved to the left between the cardiac swelling and the body stalk.
The marked coccygeal and pehde curve is seen from the left as a hook-like process. The tail is conspicuous as is usual in human embryos of this age.
In the posterior region of the trunk four parallel ridges are present; two belong to the axial zones, the medullary and somitic ridges; two belong to the parietal zone, the Wolffian and marginal ridges. There are thirty somites present.
The upper extremities are simply oval mounds; they have not become plate-like as yet. The lower extremities are but ill-defined ridges.
The umbihcal cord is large and lies on the left side; a similar condition is found in the embryos described by Mall, Waldeyer, and Janosik, a departure from the usual right-sided position of the cord in human embryos.
C. The Anomalies of an Anencephalic Monster - Complete Craniorachischisis
The specimen represented in figures 14, 15, 16, and 17, was given to the author by Dr. J. S. Foote, Professor of Pathology Creighton University Medical School, in 1914. No clinical data were obtainable. The specimen, approximately eight months, old, weighed 1.500 grams, and was 20 cm. in length from the breech to base of skull at its dorsal aspect.
The interesting fact in regard to the anencephalic monsters is that they are usuallv of the female sex : the monster under consideration was a female. The marked abnormalities are the absence of the brain, spinal cord usually, and lack of development of the bones of the vault of the cranimn and of the lamina of the vertebral colmim.
Ventral aspect (fig. 14.) : The anns are in an unnatural position They were forcibly drawn lateral to the lower limbs in order to procure a clearer view of the face and ventral regions. The striking feature is the attitude of the head. It is sunk between the shoulders and extended. Owing to the absence of the cranial vault, the face is very prominent. The tongue protrudes from the mouth, the eyes project markedly from their sockets and look upward. This is due to the fact that the forehead is abnonnally sloped backward, the supraorbital plates are rudimentary and are necessarily tilted in the same direction as the forehead. The nose is broad and flat and the mouth is partly open.
The broad shoulders and the general plump appearance of the trunk and the overdeveloped upper extremities present a curious contrast to the defonned head. The excessive development of the shoulders and upper limbs usually gives rise to serious dystocia. The abnormal shape of such a head generally leads to face presentation. Owing to the exposed condition of the base of the brain, there is frequently a marked increase in the amniotic fluid.
There is a partial development of the frontal, parietal and occipital bones towards the narrow base of the skull. These rudiments slant mesiad and are not prominent. The brain is represented by a conglomerate mass of membranes, blood-vessels, and connective tissue. There is absolutely no trace of nervous tissue of the cerebrospinal axis. These i-udiments of the central nervous system, just enumerated, entitle this monster to be classed as a pseudoencephalus, according to Geoffroy Saint-Hilane, who reserves the term anencephalus for those monsters in which absolutely no membranous rudiment of any kind is present.
No neck is definable. The umbilical cord possessed one vein, but only a single artery, a fact noted by Gillaspie and Henston ('17) in the anencephalus described by them.
Right lateral aspect (fig. 15). The partial development of the frontal and parietal bones and their marked slope inward is well shown. The exposed membranes, connective tissue and bloodvessels are seen as a protuberance on the dorsocephalic aspect of the head. The well-developed and plump appearance of the trunk and upper lunbs are seen in this view, and forms a decided contrast to the abnormal head. The slit on the lateral aspect of the right thigh was made in taking out the femur.
Dorsal aspect (fig. 16). The condition of craniorrhachischisis is apparent. The lack of development of the calvarium. consisting of the squamous part of the occipital, parietal bones and frontal bone, is well sho\Mi. The membrane and connective tissue over the dorsal aspect of the base of the skull and floor of the vertebral canal, which is wide open, were left intact. The edges of the peduncles of the vertebra form a contmuous ridge on both sides of the wideopen vertebral canal. These are seen as fight linear ridge? on both sides of the dark groove. The broad well developed shoulders stand out prominently.
Left lateral aspect (fig. 17). The more marked buigmg of the left eye is better seen in this view. The lack of development of the left supraorbital ridges together with its acute slope inward causes this eye to look upward and to protrude more than the right eye. The eversion of the right foot and inversion of the left are manifest. The club-foot condition of the former is of the tafipes calcaneus variety: of the latter, of the talipes varus variety.
The topogaphical relations within the thorax were nonnal. The lungs and th\Tnus showed no marked abnomiafities. The heart showed a high degree of defect in its septa both in the atrium and in the ventricle. The septum primum and septmn secundum of the auricular partition were nidunentary, lea\-ing an abnormally enlarged foramen ovale. The ventricular septum was represented Idv mere ridges. The auricular-ventricular valves were quite inadequate and did not function as valves at all. There was evidently marked cardiac incompetency.
In the abdomen the intestines, liver, pancreas, spleen, kidneys, and suprarenals were normal. It has previously been pointed out that there was but one umbiUcal artery. Upon dissection this proved to belong to the left side. A persistence of but one umbiUcal artery belonging to the right side was pictured and described by Gillaspie and Henston ('17). In their specimen the uterus was displaced to the left, owing to the fact that the aorta was directly continuous in the median hne with the right h\'pogastric artery. In my specmien a similar arterial condition existed in the pelvis with the difference that the persistent umbiUcal artery belonged to the left side which in turn caused a displacement of the uteiois to the right instead of to the left.
Although the muscular system was dissected and studied, no detailed report will be made here except to state that a stemalis muscle was found on both sides in this specimen, but not in the second monster. The arteries to the limbs were nonnal as well as the peripheral nervous system. The condition of the skeleton is well depicted in the skiagraph, figures 16 and 17. Note especially absence of the spinal lamina as well as the cranial vault in the dorsal aspect (fig. 16). The base of the skull was accessible to the examining finger. The sella turcica and the anterior and posterior clinoid processes were easily palpated.
The styloid process of the right side is precociously ossified and throws a dark shadow in the skiagraph.
In consequence of the ill-development of the laminae of the cervical vertebrae, there is a lordosis in this region (lateral aspect skiagraph). It is also definitely seen that there is a compensatory kyphosis of the upper thoracic vertebrae, extending the head and allowing it to sink between the shoulders, and giving the fetus an attitude characteristic of many forms of deficient head and spine development. There is also present a marked kyphosis in the lumbar region beginning at the twelfth thoracic vertebra and extending to the first sacral vertebra.
The position of the mandibula and the protrusion of the tongue, which are really an exaggeration of the first act of deglutition, are to be attributed to the unperfect development of the temporal muscles, allowing the depressors to predominate. Of the temporal muscles only the fascicuh arising from the lower part of the fossa are present ; these insert upon the coronoid process. They thus are largely representative of the posterior part of the muscle, which is active mainly in retracting the jaw. The large anterior portion, which elevates the jaw, is absent.
All the mandibular depressors are present, with only the small masseter and the internal pterygoid to oppose their action. Accordingly, the typical open mouth of anencephalic monsters is correlated to the defect in the cranial vault and the associated loss of the anterior portion of the temporal muscle.
D. A Second Anencephalus Monster - Complete Craniorachischisis
This specimen was given to the ^mter in December, 1917, by Dr. T. J. Dwyer, Associate Professor of Surgery, Creighton University Medical School. It was prematurely bom at eight mqnths and at first presented by the face. However, because of the overdeveloped shoulder, even more marked than on the forgoing specimen, an obstruction was presented to the descent of the child which called for podalic version. There was a marked condition of hydramnios. Before birth, at six months, the child had been predicted by Dr. Dwyer to be an anencephalos. This condition was suggested by the hydramnios and the exaggerated intensity of the fetal movements which were also irregular and spasmodic in character.
The monster was a female. The condition of craniorrhachischisis was more extensive than in the fonner specunen. The spina bifida extended through the coc€jtc. Absolutely no remnants of the calvarium were present. No membranous rudunents were found and only a slight amount of connective tissue covered the base of the skull. Both eyes bulged even more prominently than the left eye of the first specimen because of the greater slant and arrest of development of the supraorbital ridges and plate.
Two arteries and one vein were found in the umbilical cord. No stemalis muscle was found. Outside of these differences the description of the first specimen holds for the monster under consideration; but the abnormalities of the heart are if anything more extensive.
Ahlfield ('80) assigns as the direct and immediate cause of anencephalic monsters, hydrocephalus. If the serum accumulates early within the ventricles, the bram and its covering are ruptured at about the fourth week of embryonic hfe, they atrophy and disappear and the result is anencephalous. The accumulation of serum may make it impossible for the bony case of the brain to enclose the cranial cavity, causing thus varying defects of the skull through which the membranes and their contents protrude. If the serous effusion affects the spinal region as well as the cranial cavity before closure of the neural tube, which is thus prevented, there is an associated spina bifida resulting therefore in the condition of craniorrhachischisis.
The primary cause of hydrocephalus can only be surmised. Many have made a vague reference to the already overworked amniotic bands. It is interesting to note that Morgan has experimentally produced spina bifida in the tadpole of frogs by subjecting the eggs to a 0.6 per cent solution of common salt. This retards development and results in posterior spina bifida. In regard to the underlying cause of anencephalic monsters with spina bifida. Mall ('10) concludes: "It is no longer necessary for us to seek mechanical obstructions which may compress the umbilical cord, such as amniotic bands, for it is now clear that the impairment of nutrition which naturally follows faulty implantation or the various poisons which may be in a diseased uterus, can do the whole mischief."
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