Nerve injury

Damage or severance of conducting fibres within a nerve as a result of trauma, causing loss of skin sensation and muscle power. (See neuropathy for nerve damage from causes other than injury.) If a peripheral nerve (a nerve outside the brain or spinal cord) is only partially severed, the cut fibres may be able to regenerate. Provided the severed ends are still aligned, new fibres can grow across the cut to rejoin the connection, restoring function. If a nerve is totally severed, the individual fibres cannot regenerate successfully and there is no recovery of function. Nerve tracts within the brain and spinal cord are structurally different from the peripheral nerves, and severed fibres in these tracts do not regenerate. For example, vision cannot be restored if the optic nerves are cut. Microsurgery can sometimes be used to stitch a severed peripheral nerve into place, but recovery is rarely complete.