Tarsal tunnel syndrome due to a ganglion: a case report.

TARSAL tunnel syndrome is the pedal equivalent of carpal tunnel syndrome. The common aetiology of a tunnel syndrome is the compression of a nerve as it passes through an inextensible compartment. The nerve involved is the posterior tribial as it passes deep to the flexor rectinaculum, postero-inferior to the medial malleolus. The nerve divides to form the medial plantar, lateral plantar and calcaneal branches which together supply the small muscles of the sole of the foot and cutaneous sensation over the toes (Figure). Patients present with pain or paraesthesia over the distribution of one or more of the branches of the posterior tribial nerve. Diagnosis may be confirmed by nerve conduction studies in which prolonged conduction latencies can be demonstrated. It is a rare condition, often missed clinically or mistaken for other more common conditions e.g., plantar fasciitis or interdigital neuroma.