Laproscopic view of the uterine folds

The uterus is suspended in the pelvic cavity by the broad ligament (mesometrium). The uterus is supplied with blood on each side with three artery/vein pairs. Rupture of these arteries may occur during parturition in aged mares resulting in a hematoma in the broad ligament or a fatal hemorrhage into the abdomen.

In a normal, nonpregnant mare, the uterine lumen is not visible because the walls of the uterus collapse. In the image above, air was used to expand the uterine body and a laproscope used to observe the lining of the uterus. The lining of the uterus (endometrium) forms longitudinal folds. The folds are more prominent during estrus due to effects of estrogen. The folds are easily seen at estrus with ultrasound.

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