In 1916, Geoffrey Jefferson, a hospital pathologist in British Columbia, took time to dissect, stain, and examine ten prepuces under his microscope. He expected to observe simple flaps of skin. Writing up his findings, however, he professed astonishment as the amount of muscle tissue in his specimens and the complex connections of the peripenic muscle within the muscular structure of the penis. This laboratory research, along with his experience in the clinic, led him to conclude that the foreskin was unusually dynamic, both in muscular activity and in long-term development from infancy to maturity.

The prepuce is not just a fleshy cover. It serves as a platform for nerves and nerve endings. Indeed, the density of nerve fibers, particularly in the outer skin of the prepuce, make it as sensitive to light touch – and to pain – as any other part of the organ.

The most remarkable feature of the prepuce had to do with the differences between its inner and outer surfaces. Its exterior is like the skin that covers much of our bodies. Its inner lining, however, is a type of skin found in only a few places in human anatomy. Tiny protuberances called papillae stud the cell surface, and there are microscopic bundles of nerve endings that again resemble those in the inner lining of the mouth. Unlike the surface skin of the penis, which becomes toughened by exposure to the elements, the prepuce’s inner mucosa never forms a dense collagenous layer.

During erection or when the prepuce is manually pulled back, the band is turned inside out on the shaft of the penis. The ridged band is more like the skin of the lips, forming a transition between the facial skin and mucous inside the mouth.

The prepuce itself is a physiologically complicated structure with specialized parts that serve different functions. The “ridged band,” for example, is made up primarily of sensory tissue whose neural structure differs from that of the glans. Presumably, in the dynamic flow of sexual activity, its contributions to sensation are unique.