The Anatomist - Bill Hayes [79]
As a time-saver, deskinning of the upper thigh was supposed to have been done in advance by the teaching assistants, but they had obviously run out of time before getting to our table. I don’t mind. I look upon it as a chance to pay extra-close attention to the layer of “superficial fascia” that undercoats the skin. In appearance, superficial fascia is as different from the second type of fascia, “deep fascia,” as apples are to oranges; in fact, it brings to mind oranges, fittingly enough. If you could invert your skin, à la an orange rind turned inside out, you would find the entire surface lined with a similar soft, spongy whitish material. That is superficial fascia. It makes for a great insulator and acts as a support structure for sweat glands and superficial nerves and blood vessels. By contrast, deep fascia is more fibrous and therefore tougher than superficial fascia, and, as its name indicates, it is located deeper within the body. In the thigh, deep fascia is called fascia lata, so named, Gray explains, for its “great extent” (lata meaning “broad”), and, sure enough, I find this taut, opaque tissue wrapped around the full extent of the thigh like a big Ace bandage. It not only binds the thirteen meaty muscles within but also intensifies the force they generate.
To cut it apart, I choose scissors. With the tip, I puncture a hole in the fascia lata at the lap line, then scissor downward to the middle of the kneecap. It is as easy as cutting fabric. I make crosscuts at the very top and very bottom and peel the long double doorways back.
I have just cut my way into what’s called the anterior compartment of the thigh, the largest of three fascia-walled sections surrounding the femur bone. Each compartment is literally a discrete room housing a set of muscles related to one another by function. For instance, the thigh’s main extensor muscles, which help extend the leg, are all bundled together in the anterior compartment. My next task is to unbundle them.
There is no better tool for this than the fingers. (Gloved fingers, mind you.) I press into the mass of undifferentiated fibers, feeling for seams. Deep fascia binds these individual muscles together as well, but it’s of a different consistency here—more like a sticky fluid, viscous and clear—and I easily work the muscles apart. The first to pull free from the pack is the sartorius, the longest muscle in the body, which extends from the hipbone to the inside of the knee. By running it between my thumb and fingers, up and down, up and down, I am able to clean its whole length. But in the pulling apart, I have broken the fascial bonds that give the muscle stability and support. The sartorius now drapes across the thigh like a sadly sagging sash.
Unbeknownst to most people, the human body has several biceps (a single muscle with two parts, or heads); the biceps that bulges when someone says “Make a muscle” is simply the most famous. There are two triceps muscles, triple-headers. But there is only one quadriceps, the quadriceps femoris (or, as it is commonly known, “the quads”), and it forms the main bulk of the anterior compartment. As I separate and clean each of the four muscles, I find myself dissecting dissection itself. How would I explain this to someone, I start to wonder, the satisfaction that one derives from dissecting?
The pleasure, I decide, lies in making order of the disorder, in tidying up what looks messy. It is an art well suited for fastidious types such as myself. “Make it pretty,” Kim and Dana often instruct, half seriously, but it’s true—that is exactly what one strives to do. When done well, dissection is very pleasing aesthetically.
With the anterior compartment completed, I move on to my final task, the dissection of the “femoral triangle” in the upper inner thigh. If you make