Part 28

Diseases of the lower parts of the urinary tract are not numerous and of incidental interest only; many are associated with or due to lesions in the genital organs, and will be referred to later. Cystitis is uncommon, only being observed some four times unrelated to prostatitis and vesiculitis. Two of these cases were secondary to a traumatic urethritis. No stones have been seen. A mixed cell sarcoma was found springing from the bladder wall in a Richardson’s Kangaroo Rat (_Perodipus richardsoni_). The written record has unfortunately been lost, but the preserved slide confirms the original diagnosis. Rupture of the bladder occurred in a Gray Fox with stenosis of the end of the penile urethra causing retention and secondary cystitis. Another stricture of the urethra in an Ocelot (_Felis chibigonazon_) caused great dilatation of the bladder. This animal is thought to have chewed off all the external genitalia because of lice, with the result that the stump of the urethra became involved in a contracting cicatrix. Opossums, raccoons and wild dogs have shown light cases of urethritis seemingly traumatic in origin, and two dogs had cystitis and urethritis associated with what was believed to be distemper.

SECTION IX THE FEMALE REPRODUCTIVE ORGANS

The mechanism and organs of reproduction differ so widely in the classes under discussion that it will be necessary to describe separately the alterations in mammals and in birds. Examples of abnormality and disease are not very numerous and I shall cite cases for many of the conditions rather than prepare comparative lists as has been possible in many foregoing sections. Some years ago Dr. Edward A. Schumann[40] studied the comparative anatomy and physiology of the mammalian female generative organs, and I shall condense and paraphrase his work. (The complete articles may be found as in the references below.) This gentleman, because of his gynecological experience and broad interest in comparative biology, has been consulted whenever unusual material from this tract has presented itself so that many of the descriptions that I shall employ are due to him. I take this opportunity to acknowledge with thanks his interest and helpfulness.

COMPARATIVE ANATOMY IN EXPLANATION OF HUMAN UTERINE ANOMALIES.

The development of the genital tract seems to be essentially the same through all orders in that the genital ridge forms the ovary and its attachments while the Mullerian ducts supply the tubes, uterus and vagina. Early in fetal life these two longitudinal ducts begin to approach one another, and by the end of the third month should be in the position which they are to retain for the full development of their end result. In the human being this position is complete union and fusion, with the production of a single tube from the uterine fundus to the exterior, while in the lowest mammals, edentates and marsupials, the two Mullerian ducts retain their lateral position, and upon completion of embryonal life a double tube from the ovaries to the exterior is found. If the normal fusion of the ducts does not take place, and if for any reason their proper relation is not reached, an abnormality will result varying according to the stage of development that has been reached. Thus in man instead of a single uterus of triangular shape and a single cervix, a double set of tubes may be found. It can be shown that the abnormalities of the human uterus are of definite and fixed types corresponding to an arrest of fusion or completion of the developmental cycle as given for the Mullerian ducts and further that these very deformities are comparable to normal organs of lower orders. In other words abnormalities in arrest of development in the human uterus represent normal types of lower uteri at various evolutionary stages. In monotremes there are two ovaries, tubes, uteri, cervices, a urogenital passage and a clitoris. This corresponds with Uterus didelphys with a single vagina. This abnormality while occurring in the lowest mammal, does not represent the most marked deformity known for the human being— that in which the double tube remains to the vaginal outlet, a condition found in the marsupials. In this order the uteri are entirely separate, and each is fitted with its own vagina. The next higher order, Edentata, seems somewhat out of place if it be judged by its female genitalia since it is possessed of a triangular uterus and single vagina but without distinct cervical segment; the tract is very similar to that of the Primates.

Rodents, in the various families, present no uniform uterine construction, there being four kinds corresponding to as many degrees of Mullerian duct fusion and differentiation. The lowest forms simulate the marsupials, another group is like the monotremes, a third shows a complete fusion with a single cordiform uterine body, while the last resembles somewhat the first, but the uterine divisions are bound together and the vagina is divided only half way down. The Insectivora occupy a transitional position resembling higher and lower groups in having a long uterovaginal canal, without distinct cervix, extending upward into long curved cornua. Cetacea (whales) have a highly rugous single vagina, a distinct, short uterine segment divided into two separate horns. The genitalia of Sirenia resemble those of the last group, but the cervix is better developed. In the last three orders the clitoris begins to be well developed and to present externally. Proboscidea have a single vagina separated from the short uterine body by three transverse folds corresponding to the cervix; the two cornua are long and wide.

“The foregoing orders present in their uteri all the essential characteristics of uterus bicornis unicollis with single vagina and are therefore the homologues of this anomaly in man.”

In the Perissodactyla, the bicornate uterus has a body of a little less than half the whole length; there is a sphincter at the lower end of the body but no projecting cervix. The cornua are longer still in the Artiodactyla and are coiled in a manner suggesting spiral sheep’s horns; there is a differentiated projecting cervix. In cats the length of the uterine body and of the cornua are almost equal and both are flat tubes; the cervix is prominent and the vagina long and rather smooth. The dog’s uterus is similar but the two cornua are bound together or fused before the point at which their termini enter that of the uterine body; the cervix is not very prominent, but well formed and the vagina is rugous. These types correspond to the uterus cordiformis. Lemurs have a common uterovaginal cavity like the Edentata. The lower monkeys possess a long slender uterus with definite superior lateral angles, the last vestiges of the cornua, a prominent cervix and a short rugous vagina. The higher apes have a uterine construction almost identical with that of man at the stage of infantile development.

“From the foregoing study it is clearly shown that every anomaly of the female genitalia in Man is in reality the result of atavism and hence, a degenerative change, and inasmuch as every special form of anomaly finds its counterpart in the normal anatomical arrangement of the analogous structures in one or another of the great mammalian groups, one additional item of proof is offered in support of that greatest of biological doctrines, the descent of Man from the lower forms of life.”

ANATOMY OF LABOR.

In a second article Schumann reviews the comparative anatomy of labor, demonstrating that the basic principles are essentially the same, alterations only being in the direction of accommodation to the pelvic construction. In order to make the analysis comparable with human conditions the pelvis is studied as if the animal were standing erect upon the hind limbs.

The salient points of difference between the quadruped pelvis and the biped, human type may be epitomized as follows: (a) The entire pelvis lies (with the animal in its normal station) in a generally horizontal position with a slight slope downward anteriorly. (b) The false pelvis is almost entirely wanting, there being practically no bony structures above the brim with the exception of the small upper portions of the ilia. (c) The pelvis in quadrupeds is never basin-shaped, the lateral walls from the iliac crests to the tuberosities of the ischia lying roughly parallel to each other and enclosing a pelvic cavity rectangular in outline. Only in the highest apes does the basin-shaped pelvis appear. (d) The angle of the axis from the promontory of the sacrum to the symphysis is always greater in the quadrupeds than in man, averaging in the former from 70 to 80 degrees, in the latter about 55 degrees, (e) The symphysis pubis is an extremely long joint, being frequently greater than half the length of the entire pelvis, (f) The sacroiliac joint is more or less movable in all quadrupeds, especially in young animals. The rotation of the sacrum on the ilia increases the anteroposterior (dorsoventral) diameter of the outlet and at the same time wedges apart the ilia, thus increasing the lateral diameter.

In regard to the forces of labor it is to be pointed out that in the lower mammals the pregnant uterus hangs below the pubic arch so that the fetus must rise at an angle of about 45 degrees to pass over the pelvic brim. In so doing it meets the narrowest part of the triangular bony pelvic inlet, the anterior pubic angle. Since the sacrum is above and out of the way, the lateral diameter is the one which must be suitable to the passage of the presenting part. This is the head in homo, the largest part of the fetus, but in lower animals either head or breech often accompanied by one or more extremities, may present; the head is not the largest part in lower mammalian fetuses. The uterine contraction proceeds as in man, the fundus and cornua acting alone until the cervix contains the fetus, at which time all parts contract. In the bicornate organ both sides must contract or the fetus might be forced from the gravid to the empty side. In multiparous animals with both uterine horns occupied, the fetuses lie head to head, breech to breech and are expelled alternately from each side.

In uniparous animals rotation is in the nature of an accommodation of the greatest diameter of the fetal body in cross section to greater axis of the mother—the dorsoventral. Uterine contractions cause the fetus to unfold from its elliptical form and to assume an extended position, permitting head or breech to enter the lower pelvis. The pubic angle having been passed and the extension of the presenting part being successfully accomplished, there is no striking difference in the manner of external expulsion of the fetus.

DYSTOCIA.

Dystocia in domesticated animals is a well studied subject, and its general clinical phases are fairly well known. Several cases have been observed, details of which are worthy of note since some of them are entirely complete.

Inertia uteri as a single non-obstructive condition seems not to have been observed here, although well enough known to veterinarians. Nor has a case of dystocia been seen as the result of excessive expulsive force. Obstruction to natural passage by bony deformities or malformations is a common occurrence in man but not so in lower animals. There may also be dystocia by reason of a normally formed but too small pelvis when the female has been impregnated by a much larger male, or if the female conceived before the pelvis has achieved its full growth.

Deformities may be due to irregularities of bony development, exostoses, fracture or diseases of the osseous system. A most interesting case of this type occurred in a Barbary ape (_Macacus innuus_) which had been in the collection for two years and was apparently in good health when discovered in labor.

No progress being made and the animal becoming shocked, an ineffectual attempt was made to deliver by version, the monkey dying during the operation. Upon autopsy the uterus contained a fetus apparently at term. The head was extended so that the face presented, but the head was not engaged. The cervix was fully dilated but the uterine muscle was relaxed and flaccid. The fetus was dead when the animal was first examined. The uterus contained two placentæ as is normal for these apes, the left placenta being the place of attachment of the fetus while the right one was somewhat smaller and presented no umbilical cord. The fetus was normal in size and form, the face was extended and its lower portion far advanced in a caput succedaneum. The measurements of the fetal were as follows: bitemporal 5.5 cm., biparietal 6 cm., occipitomental 8.5 cm., occipitofrontal 7.5 cm. The pelvis (dried specimen) presents a most interesting condition. The sacrum is bent sharply forward, carrying with it the border of the ilia, which are bent upon themselves forward and downward. The lateral walls of the pelvis are greatly narrowed, the ischia drawn inward. The pubes and the symphysis are fairly normal. The pelvic measurements are: diagonal conjugate 6 cm., true conjugate 4 cm., greatest transverse 4 cm.

It is apparent at a glance that here was an impossible labor, since the head of the fetus could not possibly enter the pelvis, the size of which, _intra vitam_, must have been less than the above measurements by reason of the soft parts. “This is in the experience of the writer a unique case of a complete obstetric history, plus the specimens, of labor with an osteomalacic pelvis in a wild animal.”

Another case may be added to those already reported by Dr. Schumann, as follows:

Hairy rumped Agouti (_Dasyprocta prymnolopha_). Dystocia. An apparently normal fetus occupies the left uterine horn. The nose was engaged in the pelvis and has been moulded in a curve pointing to the right. The fetus measures—bitemporal 30 mm., cervical-coronal 31 mm., length of fetus 17 cm. Pelvic inlet in the fresh state measures 18 mm. transversely and about 17 mm. anteroposteriorly. The umbilical cord is 10 cm. long and appears normal as do the membranes. Placenta presents as a spherical mass of hard dense consistency, 35 mm. in diameter and with apparently normal placental tissue occupying the lower border of this spherical mass. On section the mass shows areas of alternating soft red tissue separated by communicating trabeculæ of dense white fibroid tissue. This mass is distinctly encapsulated, but the nature of the enclosing membrane is indeterminate. The pelvis in dry state shows evidences of malformation due to trauma. The right ileum is pushed forward and inward carrying the acetabulum a short distance inward and backward. There is a marked thickening about the right acetabulum. At the upper portion of the symphysis there is marked bending backward toward the sacrum with thickening of the bone. The last sacral vertebra is sharply bent and anchylosed, forming an angle of sixty degrees. The pelvic measurements in the dry state—at superior strait-transverse 24 mm., right oblique 23 mm., left oblique 26 mm., true conjugate 22 mm., outlet 17 mm., between the ischiatic spines.

This is obviously a traumatic malformation and forms a relatively contracted pelvis. The delivery of an adult fetus is impossible.

Cape Hyrax (_Hyrax capensis_). Impossible labor due to malformation of the pelvis. This animal died as the result of shock and exhaustion of labor. She was pregnant of two fetuses, one of which was extracted manually by the keeper but was dead at birth. Twenty-four hours later the animal was found dead. On autopsy there was present a fully developed fetus in the right cornu, the head just above the pelvic inlet. The left cornu was large and boggy. The myometrium of the right side was so thin as to be almost transparent. On examining the bony pelvis the reason for the dystocia is at once apparent. The sacrum is tilted to the right, and the body of the left ileum is bent sharply to the right, the pelvic inlet being obliquely contracted, the right oblique diameter being 16 mm. while the left is 23 mm.

The pelvic obliquity made the birth of a full sized fetus impossible, the one delivered being under developed. The myometrium was evidently stretched almost to the point of rupture when death occurred.

Obstruction to the birth canal by abnormalities in the soft parts, such as muscular rigidity, edema, or inflammation, tumors, atresia or developmental defects are occasionally seen by veterinarians but have not been encountered here.

Dystocia from uterine displacements are uncommon except such as may depend upon the failure of support by the abdominal wall, since this is the principal support of the organ especially when gravid. Hernia or hysterocele is known and anteflexion has been seen. Torsion, a rare human condition, is not uncommon in lower animals probably due to the loose dependent position of the pregnant cornua, attached only to the pelvic walls by slender inactive suspensory ligaments. A case may be reported, not originally described.

Canada Porcupine (_Erethizon dorsatus dorsatus_). Obstructed labor. This animal died from exhaustion due to an impossible labor. On autopsy the abdomen contained a moderate amount of clear serous fluid with one small blood clot. The right uterine cornu was distended with a fetus to about the same diameter as the uterine body. This cornu was congested and edematous and its walls very thin. The cornu was twisted one-half full turn from right to left, so that the pregnant portion overlaid the uterine body anteriorly. The torsion produced a compression of the vessels on the right side to the point of violent congestion of the cornu. There was no apparent rupture of the uterine walls, death having occurred from exhaustion. The fetus and its membranes were normal.

Many forms of abnormalities in position are recognized for domesticated animals, but since we know so little of the early stage in the wild specimens no data can be given.

Complicated labor in lower varieties of animals will follow lines similar to those for man and domesticated animals. Hemorrhage from trauma is not common at term, but several cases of abortion following injury have been seen. Postpartum hemorrhage might be expected in the higher apes which have a large discoid placenta similar to the human form, but when the placenta is more loosely attached and is subdivided as in lower forms, such bleeding is of no danger; when a cotyledon is torn from the ungulate uterine wall, a free hemorrhage sometimes occurs.

Geoffroy’s Marmoset (_Leontocebus geoffroyi_). Puerperal relaxation of the uterus with fatal hemorrhage. The uterus is 4 cm. long, 15 mm. wide at intertubal line. Uterine wall averages 2 mm. in thickness. Peritoneal surface is smooth, glistening and intact. Uterine musculature is soft and relaxed. Entire organ is intensely congested and on section uterine cavity contains a large firm blood clot completely filling it. Mucosa is of deep purple color, shows many fragments of decidua and is the seat of profuse hemorrhage.

Placenta previa is very rare. A row of cotyledons may form near the internal os, therefore like a placenta previa, but it appears to be of no consequence. Premature separation of the placenta is known to veterinarians, and is exemplified by the following case in our records:

Black Lemur (_Lemur macaco_) was found dead in its cage. Upon autopsy the uterus contained a small fetus with one leg and the tail protruding from the vulva. The fetus was normal in size. There was a large amount of free blood in the uterine cavity and extensive extravasation into the myometrium. The placenta was completely detached.

Rupture of the uterus and cervix have not been seen, but a traumatism of the vagina gave occasion for the following death:

Bactrian Camel (_Camelus bactrianus_) died of shock in labor. Upon autopsy the animal was found to have hydatid disease of the liver, lungs, and spleen, cirrhosis of the liver, and nephrolithiasis. Protruding from the vulva was a portion of the fetal membranes, the whole vaginal wall and several coils of intestine which had escaped through a large rent in the posterior vaginal wall. The anterior wall was swollen and edematous, the whole region surrounded by clotted blood. The cervix was obliterated, the membranes unruptured, the fetus in the normal extended head presentation. The veil-like placenta was somewhat injected but otherwise normal. There was some hemorrhage about the rectum but none in the free peritoneum.

This animal had broken her hind leg just above the fetlock three weeks before falling into labor, and was unable to stand. It is evident that the difficulty of delivery associated with an unnatural and forced posture due to the fractured leg was sufficient cause for the rupture of the vagina where the tissues were degenerated as a result of the coincident general disease.

Inversion of the uterus is one of the common accidents of labor among all animals, most frequently seen in ruminants. It is a condition more to be expected in lower animals than in man because of the long slender relaxed suspensory ligaments, the length of the uterus and the rigor of the contractions. The immediate causes are those operative for human beings. Three cases are recorded—one in an axis deer, one in an opossum, one in a mouse, the last being detailed in the following notes:

A Japanese Waltzing Mouse (_Mus wagnerii rotans_) died a few hours after an uneventful labor. On autopsy the entire uterus was found inverted and prolapsed, the organ the seat of a violent congestion, the animal having died of shock.

THE PELVIS.

A study of the dynamics of the female pelvis from an evolutionary standpoint may explain some of the difficulties attending parturition. Starting from the biological law that morphology follows function and that the anatomy of a part alters to suit a changed physiology with such modifications as are necessary to fit each part properly to interact with other structures comprising the entire animal, it is evident that two great changes have occurred in the evolution of homo—the assumption of the upright posture and an increase of intellectual power necessitating a larger cranium of modified form. To this end also the pelvis would have to change both for support and to allow the passage of the enlarged head. The functions of the pelvis are (1) to attach the legs or hinder limbs to the trunk; (2) to furnish points of attachment and fulcra for the great muscles which move the limbs, and in the case of man, hold the trunk erect; (3) to provide egress and support for the terminal canals of the intestinal and urinary systems; (4) to provide for a birth passage; (5) to act as a shelf and support for the abdominal viscera. In quadrupeds the first four functions being perfectly served, there are fewer abnormalities of reproduction (and in the positions of viscera as well—ED.). In man natural selection weeded out narrow pelves, but the present product is as yet an imperfect structure for one of its main uses, parturition. It should be a funnel-shaped basin of the shape of the fetal head and of the same height at all points—that is not oblique, there should be no promontory, the pelvic symphysis should be short and the sacrum of the same height. This would obviate internal rotation now necessitated by the oblique pelvis; this does not occur in quadrupeds.