CHANGES IN THE NON-PREGNANT UTERUS 77 



uterus is also supplied by nerves whicli are referred to in a 

 future chapter (p. 527). 



In many of the lower Mammals the uterus is represented by 

 two tubes, called the horns of the uterus or uterine cornua, 

 which may unite posteriorly to form the corpus, or may, on the 

 other hand, open separately into the vagina. The arrangement 



Fig. 3. — Section of a cornu of a rabbit's uterus. 



Serous layer ; Im, longitudinal muscle fibres ; cm, circular muscle fibres ; 

 ii, areolar tissue with large blood-vessels ; mm, mnscularis mucosse ; m, 

 mucosa. (From Schafer.) 



of the different layers in each of the cornua is essentially similar 

 to that presented by the corpus uteri in the human species. 



The neck or cervix uteri, which is narrower than the rest of 

 the organ, opens into the vagina by a transverse aperture 

 known as the os. The vagina is the broad passage from the 

 uterus to the exterior. Its walls contain both longitudinally 

 and circularly arranged muscle fibres. Internally it is Uned 



