DISSECTION OF THE DOG 115 



recto-uterine excavation of Douglas) which intervenes between the vagina and 

 the colon, and in which the colon hangs by its short mesentery. 



Dissection. — Proceed as in the dissection of the male pelvis. 



Intesttnttm bectum. — The description as given for the male rectum 

 applies also to the female. Ventrally, the rectum is related to the uro-genital 

 sinus. 



The levator ani, and external and internal sphincter muscles, as well 

 as the longitudinal muscular fibres of the rectum, have the same general 

 disposition as in the male. 



Vesica urinaria. — The description of the urinary bladder as given in 

 connection with the male pelvis applies here, with the difference that there 

 are no deferent ducts or prostate related with the neck, and the dorsal surface 

 is in contact with the vagina. The presence of longitudinal muscular fibres 

 continued from the neck of the bladder to the wall of the uro-genital sinus 

 should be noted. 



Dissection. — Open the bladder and urethra by making an incision along 

 the mid-ventral line. 



Ubethba. — The female urethra is shorter than the corresponding canal 

 of the male, and is purely urinary in function. Running ventral to the vagina 

 it opens into the uro-genital sinus just beyond the margin of the ischium. 



Obgana genitalia mtjliebbia. — The reproductive organs of the female 

 consist of the two ovaries with their associated uterine tubes of Fallopius, 

 the uterus, the vagina, the uro-genital sinus, and the external genital parts. 

 Of these the ovaries, uterine tubes, and uterus are abdominal in position. 

 The ovaries and uterine tubes have been described earlier. 



Utebtts.- — The uterus consists of two long, tubular, divergent cornua 

 (cornua uteri) and a short body (corpus uteri). The cornua are suspended 

 in the sublumbar region by duplicatures of peritoneum known as the broad 

 ligaments of the uterus (ligamenta lata uteri), and are connected with the 

 cranial end, or fundus uteri, of the body. The pelvic extremity of the body 

 is called the neck (cervix uteri) and is in continuity with the vagina. 



If the cornua be opened by a longitudinal incision, the longitudinally 

 folded character of the mucous membrane lining the interior will be revealed. 

 The cavity of the body of the uterus is small, and the part joining the vagina 

 is much constricted to form the canal of the cervix (canalis cervicis uteri). 

 The canal opens, on the one hand, into the body of the uterus by means of 

 the. internal orifice of the uterus (orificium internum uteri) ; while, on the 

 other hand, it communicates with the vaginal cavity by the external orifice of 

 the uterus (orificium externum uteri). 



Vagina. — The vagina is a long tube extending from the neck of the uterus 



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