Anomalous origin of the sural nerve in a patient with tibial-common peroneal nerve anastomosis.

Recognition of anomalous innervation patterns may be important in dealing with peripheral nerve injuries. We describe a patient who suffered injury to the common peroneal nerve (CPN) at the knee when he laterally dislocated his knee. Intraoperative nerve conduction studies during surgical exploration revealed that nerve fibers from the tibial nerve crossed over to join the CPN immediately distal to a neuroma incontinuity. The sural nerve was also found to arise totally from the CPN.