The Anatomist - Bill Hayes [54]
One might think that skin removal would be old hat by now. It is not. The process is tedious but at the same time allows the opportunity to marvel. As the point of contact between our insides and the outside world, the skin, the body’s largest organ, differs dramatically depending on what it is covering. Consider the back of the hand, for instance. In fact, consider your own. The skin here is loose and supple, to allow for the tightest balling of the fist. When the fingers are relaxed, you can pull up folds of the eyelid-thin skin, something you cannot do anywhere on the reverse side of the hand, the palmar surface, where the skin is not only thicker but tightly enmeshed with the underlying fascia. This fixed flesh makes it possible to grip without the skin’s sliding in place. The sole of the foot is likewise fixed, so you literally don’t slip on your own skin, while the skin on top is loose.
Once the back of our hand is stripped, Rachel and I try supinating the arm so that we can move on to the palm, but we don’t get very far. Rigor mortis and embalming have made the limb so stiff, we’re afraid we might break a bone in the forearm. Not wanting to hear that horrible snap—no doubt deserving of several demerits, I imagine—neither of us wants to twist too hard. Using gentle pressure, we slowly maneuver the cadaver’s arm into a fairly workable position, jutting just over the edge of the table. I brace it while Rachel begins removing the skin of the palm. This is a much slower process than the back of the hand but also more conducive to chatting. To my surprise, I discover that Rachel and I have something in common: we are “the elders” of the class. At thirty-four, though, Rachel, an avid long-distance runner, looks a decade younger. She is so petite, she has to use a step stool to work on the hand.
When Rachel reaches the crease at midpalm—the fold palm readers call your lifeline—we switch places. Continuing with her story, she explains that she is a former accountant, a CPA with a downtown firm, who’s making a complete career change. As she says this, two options pop up in my mind: either Rachel was too good at her job and therefore too unchallenged, or the opposite. “I wasn’t a very good accountant,” she admits, ending the debate.
I move from the palm to the fingers. Hardest of all to remove, I find, is the patch of skin containing the fingerprints, which almost seems epoxied in place. It is as though the body refuses to give up these marks of identity. But finally, the scalpel wins out.
Denuded, our hand is a handsome specimen, carpeted in plush, pinkish fascia. I now use the back of a probe to separate the trio of muscles nestled in the ball of the thumb. This plump part of the palm is known as the thenar eminence, or, in palmistry, as the Mount of Venus. Two muscles run on top and another beneath, this deepest one being one of the most important in the entire human body, the opponens pollicis, the muscle that makes the opposable thumb possible. It is shaped like a small feather and is the distinctive anatomical feature that allowed our primate ancestors to handle tools and manipulate their environment in ways other mammals could not.
It gives one pause—This slip of a muscle, I think, helped advance our species—but just a pause. Then a snip.
I cut it in half to more readily find the tiny nerve that activates it, a small branching of the median nerve. Given time, Rachel and I could trace the median all the way to its point of origin, over an arm’s length away, deep within the neck. But today, we focus on just this small section, often referred to by hand surgeons as the “million-dollar nerve.” No, the dollar amount is not a tribute to the nerve’s value but is more of a penalty. If it is accidentally severed during a procedure—a carpal tunnel release,