Abdomen and Pelvis 
craniolaterally. The uterine horns rest upon the 
dorsal abdominal wall and extend to the region of 
the caudal pole of the kidneys. The diameter of the 
cylindrical uterine horns is about 2 to 3 mm and 
their length about 59 mm (Tables 4, 6). 
The two uterine horns continue as two distinct 
channels within the body of the uterus, separated 
by a septum {velum uteri), and they coalesce near 
the cervix. Thus, cranially there are two internal 
orifices (ostia uteri interna) within the uterus, while 
caudally only a single external orifice {ostium 
uteri externum) exists. On palpation, the cervix, or 
neck of the uterus, a tube 10 mm long, presents a 
firm consistency which distinguishes it from the 
vagina and uterus. 
From the cervix to the vagina, the mucosal Hning of the uterus is 
composed of simple cylindrical epithelium (Fig. 5-78) which is thrown 
into high longitudinal folds 
In the propria, which is also folded, there are transient tubular 
uterine glands lined with ciliated columnar epithelium (Fig. 5-78). 
The stratified squamous epithelium of the cervix is thrown into shallow 
folds. 
5.9.4 Vagina 
The vagina, the female organ of copulation, is a 
fibromuscular tube whose orifice {ostium vaginae) 
lies at the base of the clitoris. It is dorsoventrally 
compressed, investing the urethra ventral to it and 
enclosing the rectum to almost half the latter's 
height. 
Caudally, the vagina is lined with a keratinized stratified squamous 
epithelium; cranially, where the major alterations occur during the 
sexual cycle, the mucosa is a nonkeratinized stratified squamous 
epithelium. 
Since the European hamster has only a short 
sexual cycle (4 to 6 days) (Reznik-Schuller, et al., 
1974), the epithelium of the vaginal mucosa is 
constantly in a state of restoration, transformation 
and disintegration. Young female hamsters reach 
sexual maturity when they weigh about 200 g; at 
this time the epithelium closing the vagina disap- 
pears. Throughout hibernation, the vaginal orifice 
is tightly closed by an epithelial layer which dis- 
appears in the spring at the end of hibernation. The 
orifice is almost completely round and, depending 
on the age of the animals, about 3 mm in diameter. 
The urethra is separated from the vagina and dis- 
charges at the dorsal surface of the clitoris, which 
stands in distinct relief from the surrounding tis- 
sues and overlaps the vaginal orifice caudoventrally. 
Caudodorsal to the vaginal orifice lies the anus 
(Figs. 1-1,1-8). 
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