Anomalous tibial nerve. A case report.

A rare anomaly of a nonterminating tibial nerve is reported. It was found to be associated with tarsal tunnel syndrome. The nerve failed to divide in the tarsal tunnel and in the talocalcaneal canal distally to the Knot of Henry. The branches of the medial and lateral plantar nerves as well as the medial calcaneal nerve, the nerve to the abductor digiti quinti, and motor branches to the abductor hallucis and to the joints, vessels, and skin took origin directly from the tibial nerve. The presence of this nerve anomaly and its relevance to surgery in the posterior ankle region is discussed. Surgeons should be aware of this anomaly to avoid the inadvertent cutting of nerve branches they assume to be of a non-critical nature.