The Broad Ligaments 21 



the extent of the area between the two folds, occupied by the 

 vessels and nerves. At the posterior extremity of the genital 

 tract, where it opens into the cloaca of the embryo, the peritoneal 

 investment is interrupted and its place taken by the intrapelvic 

 connective tissue so that, eventually, the peritoneum covers, in 

 addition to the oviducts and uterus, only the more anterior por- 

 tion of the vagina ; the fusion of the two Muellerian ducts more- 

 over, to form the vagina and uterus, eliminates the peritoneal 

 covering on the median plane of each separate tube as far as they 

 coalesce, and, following this, occurs the atrophy and disappear- 

 ance of the muscular and mucous walls connecting the two, and 

 the adjacent tubes become a single canal. 



The muscular portion is composed of transverse and longitu- 

 dinal layers of pale fibers, varying greatly in the different sections 

 of the tract and also according to whether the animal be pregnant 

 or not. 



The mucous coat of the genital tract offers the greatest possi- 

 ble variations and assumes widely differing and highly import- 

 ant functions, according to the particular area occupied. 



2. The Broad Ligaments. 



Since the Muellerian ducts have their origin outside the peri- 

 toneum, it follows that in moving away from the abdominal walls 

 they must carry with them their peritoneal covering. As soon 

 as they drop away from their point of origin the investing folds 

 of peritoneum tend to meet behind to constitute a double perito- 

 neal fold, between which the vessels and nerves, along with pale 

 muscle fibres pass to and from the ovaries and genital tube. 



These expanses of peritoneum, with invested vessels, nerves and 

 muscles, constitute the broad ligaments of the uterus, or more cor- 

 rectly speaking, of the genital canal. The ligaments act as a sus- 

 pensorium for the genital tract, maintaining its connection with 

 the abdominal walls and also furnishing a support for the ovaries, 

 thereby fixing these organs, under certain limitations, in a defi- 

 nite location. The broad ligament varies greatly in its form 

 and amplitude according to species and the functional activity of 

 the genital tract. In the bitch, cat and sow, in which the anterior 

 extremities of the uterine cornua remain throughout the life of 

 the animal, as far forward as or anterior to, the posterior border of 

 the kidney, the broad ligament maintains its anterior attachment 



