_a_, Body of uterus; _b_, _b′_, horn of uterus; c, ovary; _d_, _d′_,
triangular folds connecting horns of uterus (Lig. intercornualia).
(After Zieger.)
]
The =Fallopian= or =uterine tubes= are long and less flexuous than in
the mare. The junction with the cornu of the uterus is not so abrupt as
in the mare, since the extremities of the horns are pointed. The uterine
orifice of the tube is rather large and funnel-shaped. The fimbriæ are
not so extensive as in the mare.
The =uterus= lies almost entirely within the abdominal cavity in the
adult. The =body= is only about one inch (ca. 2 to 3 cm.) in length,
although externally it appears to be much longer. This false impression
is due to the fact that the posterior parts of the cornua are united by
connective and muscular tissue and have a common peritoneal covering.
The =cornua= are, therefore, really longer than they appear externally.
They taper gradually toward the free end, so that the junction with the
Fallopian tubes is not abrupt, as in the mare. The free part of the horn
curves at first downward, forward, and outward, and then turns upward,
forming a spiral coil. The =cervix= is about four or five inches (ca. 8
to 10 cm.) long; its wall is remarkably dense, and may be nearly an inch
(ca. 2 cm.) in thickness. Its lumen, the =cervical canal=, is spiral,
and is ordinarily tightly closed and very difficult to dilate. The
=muscular coat= of the uterus is thicker than in the mare. It consists
of an external longitudinal layer and two circular strata. The inner
circular layer is about a fourth of an inch (ca. 6 mm.) thick in the
cervix. The other layers are continued in the vagina. The =mucous
membrane= of the horns and body presents as a characteristic feature the
=uterine cotyledons= (Cotyledones uterinæ). These are oval prominences,
about a hundred in number, which are either irregularly scattered over
the surface or arranged in rows of about a dozen.
In the non-gravid uterus they average about ½ to ¾ inch (ca. 15 to 18
mm.) in length, ⅓ inch (ca. 8 mm.) in width, and ⅛ inch (ca. 2 to 4
mm.) in thickness. During pregnancy they become greatly enlarged and
pedunculated. The larger ones then measure about 4 to 5 inches (10 to
12 cm.) in length, 1 to 1½ inches (3 to 4 cm.) in width, and 1 inch (2
to 2.5 cm.) in thickness. The deep face has a hilus at which the
vessels enter. The rest of the surface has a spongy appearance, due to
numerous crypts which receive the villi of the chorion.
The =uterine glands= are long and branched. The mucous membrane of the
cervix is pale and forms numerous folds. The latter are arranged in
several series which obliterate the lumen. At the external orifice (os
uteri) the folds (Plicæ palmatæ) form rounded prominences arranged
circularly, which project into the cavity of the vagina. There are no
glands in the cervix, but a thick mucus is secreted by goblet cells.
[Illustration: