Uterine retraction
Keywords: retraction, uterus, palpation, amnion, membrane, slip, uterus, ovaries, examination, pregnancy diagnosisThe image below illustrates in part, a technique known as uterine retraction. Uterine retraction is in essence, the process of bringing the whole reproductive tract into reach for easy and accurate examination. The tract is passed through ones hand without releasing it through the entire examination.
The parts of the tract and its adnexa have been labeled in the black and white image below, serving as a key for the main image.
Image size: 1224 x 638 px
There are variations as to how an operator may retract the uterus during transrectal palpation. Some may place a thumb under the lateral aspect of a uterine horn, lifting the horn so that the ventral inter-cornual ligament can be brought close enough to grasp. This technique has been referred to as "indirect" retraction. Others (including the author) prefer a "direct" method, grasping the cervix around its circumference and moving it caudo-dorsally so the intercornual ligament is elevated and made accessible.
The ventral intercornual ligament is larger and stronger than the dorsal ligament. Therefore, only the ventral ligament is used to retract the uterus.
Once the intercornual ligaments are accessible, the ventral intercornual ligament is hooked with one or more fingers. Then the uterine horns are raised and "flipped" dorso-caudally so that the tract becomes doubled over on itself. It is held in this position while the operator's hand "crawls" along the uterine horns, "feeding" them under the hand at the same time. The uterus is examined for fetal membrane slipping and abnormalities such as free fluid, tumors and so on. Like the uterus, the ovaries and their adnexa can be moved extensively in cattle. Therefore the ovary on either side can be reached easily in most animals through the "crawling" and "feeding" motions described above.
In some animals rectal tone makes it difficult to palpate structures and patience is called for. In cows with epidural anesthesia, the rectum may dilate with air, also making transrectal palpation a challenge.
Although retraction is not necessary in every case, it is usually essential for accurate assessment of the tract. When structures such as early pregnancies are not detected, it is usually because the operator has grasped sections of the uterus and has dropped the tract intermittently during palpation.
Note on retraction in other species: Although camelids do not have an intercornual ligament, the non-pregnant uterus can be retracted by cupping the whole uterus and flipping it up in a dorso-caudal direction. Great caution must be exercised when examining smaller camelids; in some alpacas it may not be possible to perform transrectal palpation safely. In horses it is neither possible nor necessary to retract the uterus for accurate transrectal examination. The equine tract is well suspended by the mesometrium, making its position predictable and easy to locate. Also, mesocervical and mesometrial tension in mares make it impossible to grasp the cervix and retract the uterus.
