The degeneration and regeneration of cutaneous nerves in experimental flaps in rats

The cutaneous nerves in pedicled flaps lifted from rats backs were studied by electron microscopy for eight weeks. On the rat back, the paniculus carnosus is supplied by cutaneous nerves from C7-8 and T1 and anastomosed with the cutaneous branch of the spinal nerves (T2 to L5), located deeper under the flap. The cutaneous nerves showed degeneration immediately after the flap was raised; four days later, unmyelinated nerve fibers had disappeared. Regeneration was observed at the seventh day. Regenerated axons of the new fibers were presumed to have originated from the few nerves placed centrally and peripherally at the base of flap, through nerve anastomoses.