[The development of hair and the restoration of innervation in the skin transplants in man].

Various areas in 7 local flaps and in 6 free skin grafts from the back, abdomen and thigh, applied to the palm and fingers and retained for periods extending from several months to 17 years are studied. After the second year, the transplants display virtually complete recovery of the sensation for pain, touch, pressure and temperature. The hair roots in the transplants have varying thickness and reveal changes in the structure of the connective-tissue and outer epithelial sheath (Figs. 1, 2). The sebaceous glands are enlarged. Isolated sebaceous glands are encountered which do not communicate with the hair roots. In the upper layers of the corium bundles of myelin nerve fibers are observed, giving off small groups of 2-4 fibers each, with slightly ascending direction relative to the hair roots (Fig. 3). The nerve fibers break down into branches which are furthermore ramified into smaller branches, forming palisade-like endings along the outer epethelial sheath of the hair root (Figs. 4-8). They number 15-25, being usually thin, with a discrete number of thickenings, and resemble the normal fibers running along the hair roots of the donor site (Figs. 9, 10). No capsulated receptors, characteristic of the surrounding skin, are noted in the transplants. Hence, it is assumed that most likely, the endings of the regenerated nerve fibers along the hair roots, although uncapsulated and with identical structure, provide for perceiving the types of sensation, inherent of the hairy and glabrous human skin.