Uterus of Different Animals
The uterus of animals is musculo-membranous sac continuous with the oviduct in front and vagina behind.
Uterus of Cow
Uterus of Cow lies almost entirely in the abdominal cavity in the adult and is attached to the upper part of the flank about a handbreadth, below the level of tuber coxae by two extensive peritoneal folds -the broad ligaments of the uterus. It consists of two horns, a body and cervix.
The horns or cornua are situated in the abdomen and are about 35 to 40 cm long. They taper gradually to the free end so that its junction with the fallopian tube is not abrupt. The horns curve downward, forward, outward and then turn backward and upward thus forming a spiral coil. The dorsal border is attached to the lateral part of flank by broad ligament.
The body is about 3 to 4 cm long. It is cylindrical and is related to the rectum above and the bladder below.
The cervix is about 10 cm long and its wall is very dense and more than 3 cm thick. Part of it projects into the vagina and is not visible externally but may be felt through the vaginal wall and the space between the projection and the vagina is called as fornix.
The lumen or the cervical canal is spiral, tightly closed and difficult to dilate. It is clearly marked off from the body of uterus and vagina so that the two orifices of the canal are distinct.
The vaginal part of the uterus is so fused ventrally with the vagina .So the fornix is present dorsally and almost absent ventrally. The cervix and body communicate through orificium internum uteri.
The cavity of the uterus is largely obliterated in the non-pregnant state by the contraction of its wall and the folds of mucous membrane. The cavity of the neck opens into the vagina at the orificium externum uteri or os uteri. In front, the uterus communicates with the oviducts.
The mucous membrane of the body and horns presents a large number of oval prominences called maternal caruncles, about 100 in number, irregularly scattered or arranged in rows of about a dozen or more. In the non-gravid state these are about 15 mm. long and a little less in width and thickness.
During pregnancy they become enlarged and pedunculated, being about 10 to 12 cm long, 3 to 4 cm wide, 2 to 2.5 cm thick.
The deep face has a hilus at which the vessels enter. The rest of the surface has a spongy appearance, due to numerous crypts, which receive the chorionic villi of the fetus. The mucous membrane of the cervix is pale and forms numerous folds. The folds are arranged in several series, which obliterate the lumen.
At the external uterine orifice, the folds form rounded prominences arranged circularly which project into the cavity of vagina. There are no glands in the cervix but a thick mucous is secreted by goblet cells.
Attachments
- The body and horns are attached by extensive peritoneal folds – broad ligaments of uterus to the lateral part of flank.
- The ligaments contain the vessels and nerves of uterus and ovaries, connective tissue and a large amount of unstriped muscular fibres, which are continuous with the uterus.
- The broad ligaments on either side gives a fold to the uterus, which extends up to the abdominal inguinal ring known as round ligaments.
Uterus of Eve and Doe
The uterus of eve and doe resembles that of the cow. The horns are four or five inches long. The junction of the uterine horns with the fallopian tubes shows no clear distinction. They are coiled in a close spiral. The body is less than an inch long. The cotyledons are much smaller than those of the cow and have a depression on their free surface.
The cervix is about an inch and a half long. The lumen of the cervix is closed by reciprocal prominences and depressions of the mucous membrane. The external urethral orifice is in the ventral part of the vagina.
Uterus of Mare
The body is situated partly in the abdomen and partly in the pelvis; it is 18 to 20 cm long. The cornua are 25 cm long and curved, the ventral border being convex. They are situated entirely in the abdomen. The junction of the oviduct and horn is abrupt.
The cervix is 5 to 7.5 cm long and the cervical canal is straight. The mucous membrane has no cotyledons.
Uterus of Sow
The body is only 2 inches long in mare. The horns are extremely long and flexuous and freely movable due to the large extent of broad ligaments.
In non-pregnant animals, they are arranged in numerous coils like small intestine. The extremities of the horns taper to the size of the fallopian tubes. The neck has remarkable length. The fornix is absent.
Uterus of Bitch
The body is very short about 2 to 3 cm long and the cornua are very long, (12 to 15 cm) straight and are situated in the abdomen in the bitch. They diverge from the body in the form of V-shape towards the kidneys. The neck is very short. The horns are not tapered gradually. The round ligaments are passing into the inguinal canal enveloped by a peritoneal pouch called processus vaginalis. The gravid uterus is abdominal and extends to the stomach and liver. Cotyledons are absent in Dog.
Uterus of Rabbit
The right and left uterus is separated for their entire length in Rabbit. The uterus has a small body and long tubular horns. The length of the horn may be one meter and presents numerous U shaped coils. The cervix is elongated and presents rounded prominences within the lumen. This arrangement helps in forming interdigitation and provides better occlusion during necessity
The wall of the cervix is continuous with that of vagina and there is no cervical projection within the vagina
