610 GENITAL ORGANS OF THE SOW 



have a depression on the free surface. The neck is about an inch and a half (ca. 

 4 cm.) in length; its lumen is closed by reciprocal prominences and depressions of 

 the mucous membrane. The external uterine orifice is in the ventral part of the 

 vagina. 



The vagina is three 'or four inches (ca. 8 cm.) long. Its ventral part contains 

 numerous lymph follicles. 



The vulva is an inch or more (ca. 2.5-3 cm.) in length. There is a very small 

 diverticulum behind the urethral orifice. The glandulse vestibulares majores are 

 inconstant; when present, they may be about the size of a small bean. The labia 

 are thick and the ventral commissure is pointed and projects downward. 



The clitoris is short, and the glans is concealed in the fossa clitoridis. 



The mammary glands, two in number, are relatively large, and are approxi- 

 mately globular, but flattened on the septal side. 



GENITAL ORGANS OF THE SOW 



The ovaries are concealed in the bursa ovarii, owing to the large extent of the 

 mesosalpinx. They are more rounded than in the bitch, and have a distinct hilus. 

 They may be situated at or near the lateral margin of the pelvic inlet, as in the cow; 

 but their position is quite variable in animals which have borne young and they may 

 be only an inch or two behind the kidney. The surface commonly presents rounded 

 prominences, so that the gland usually has an irregular lobulated appearance; 

 the projections are large follicles and corpora lutea. Mature follicles may have a 

 diameter of about a third of an inch (ca. 7-8 mm.), and corpora lutea may be found 

 which measure half an inch or more (ca. 12-15 mm.). 



The uterine or Fallopian tubes are long (ca. 15-30 cm.), and less flexuous than 

 in the mare. The fimbriated extremity forms an ampulla and has a large abdominal 

 opening. The uterine end shades insensibly into the small extremity of the cornu 

 of the uterus. 



The uterus presents several striking features. The body is only about two 

 inches (ca. 5 cm.) long. The horns are extremely long and flexuous, and are freely 

 movable, on account of the large extent of the broad ligaments. In the non- 

 pregnant animal they are arranged in numerous coils and appear somewhat like 

 thick-walled small intestine. They may be four or five feet (1.2-1.5 m.) in length. 

 The extremities of the horns taper to about the diameter of the uterine tubes. The 

 neck is remarkable for its length (ca. 10 cm.) and the fact that it is directly con- 

 tinued by the vagina without forming any intravaginal projection. When slit open, 

 peculiar rounded prominences are seen on its interior; some of these dovetail and 

 occlude the cervical canal. They are continuous behind with folds of the mucous 

 membrane of the vagina. The broad ligaments contain a large amount of unstriped 

 muscle; they also contain a large lymph gland near the ovary. ^ In the upper part 

 of the ligament the muscular tissue forms a rounded band termed the round liga- 

 ment. In an adult sow of full size it is about six inches (ca. 15 cm.) long; its 

 anterior end forms a blunt projection and posteriorly it ends in the subserous 

 tissue at the internal inguinal ring. The medial layer of the broad ligament is 

 continuous with the lateral ligament of the bladder. 



The vagina is about four or five inches (ca. 10-12 cm.) long in a sow of medium 

 size. . It is small in caliber, and has a thick muscular coat which consists of circular 



' The changes in form and position of the uterus during pregnancy are similar to those men- 

 tioned later in the case of the bitch (p. 613). 



