DISEASES OF THE GENERATIVE ORGANS 



79 



The relative size of the fa'tus to the inlet of the pelvic 

 cavity and its position are the most important factors for the 

 veterinarian and stockman to consider (Fio-. 18). On leaving 

 the womb, the ftctus passes into the vagina and vnlva. This 

 portion of the maternal passages is sitnated in the pelvic cavity 

 which continnes the abdominal cavity posteriorly. The pelvic 



Fig. 18. — Photograph of model of uterus ol cow containing a fcEtus: (B) fcetus; 

 (E) umbilical cord; (H) placenta; (A, A) horn containing fcEtus; and (C) opposite horn. 

 Note the difference in the development of the two horns. 



walls are formed by bones and ligaments that are covered by 

 heavy muscles. As previously mentioned, the ligaments and 

 muscles relax toward the end of pregnancy in order to prepare 

 the way for the passage of the foetus. Before entering the pelvis 

 it is necessary for the foetus to be forced through the inlet to this 

 cavitv. This is the most difficult part of the birth, as the bones 



