My fingers fumble blindly over curved shapes, and I hunch closer trying vainly to extend my reach into the birth canal. Trying to figure out which way the calf is coming out using just one hand is more difficult than I’d thought! Of course, it’s also more difficult if the fetus isn’t in the correct position: Calves should be born head-first, with their head resting on outstretched forelimbs like a diver. I take a deep breath and resume making large, gentle sweeps up and down, “scanning” the birth canal with my hand to form a mental picture of the fetus’ position.
I feel a broad, flat, wall-like structure that occupies the top ¾ of the birth canal, and a fist-sized knob on the left bottom side. I slide my hand between the fetus and the vaginal wall and trace a large clockwise circle as I feel around the fetus—whoops, what was that? A-ha, it’s an ear! The head is turned to the left, facing backward; the wall-like structure I was feeling is the flexed neck. Hmm ok, I’ve found the head, now I need to find the feet.
I investigate the knob more thoroughly, and I decide it’s a leg joint. However, elbows and hocks feel awfully similar out of context, and I remembered our professor emphasizing that we must feel for another joint, either above or below, to determine if we had a frontlimb or a hindlimb in our hands. I scootch further down the leg and feel a second joint and a hoof. This second joint bends in the same direction as the first joint, so I know that I’ve found a forelimb! (The hock and tarsal joints bend in opposite directions from each other.) After probing a little deeper on the right side of the birth canal, I uncover a second flexed forelimb. I retract my arm from the birth canal, careful that my OB sleeve doesn’t get pulled down, and amble over to the professor to tell him the orientation of the calf: Cranial longitudinal, dorsosacral, with the head flexed to the left, and both forelimbs flexed at the carpi.
What is a phantom uterus, you ask? It’s the nickname for a big plywood box, 4 ft x 5 ft x 8 ft, that contains a thick plastic sleeve that mimics the birth canal and uterus as it runs from a circular opening in the box through a lacquered bovine pelvic bone. A stillborn or euthanized calf is placed inside the plastic “uterus” so that veterinary students can practice various obstetrical procedures. Replacing a live animal with models is something vet schools and labs always strive for, because it’s a good balance between gaining the necessary knowledge and skills while avoiding unnecessary discomfort to animals.