The flexor retinaculum (laciniate ligament) forms the roof of the tarsal tunnel, converting the medial ankle sulcus into a tunnel transmitting the tibialis posterior, FDL, FHL tendons, and the posterior tibial nerve and artery from the medial leg to the plantar foot. The contents are arranged from anterior to posterior: Tom Dick And Very Nervous Harriet (Tibialis posterior, FDL, tibial Artery, Vein, Nerve, FHL). Tarsal tunnel syndrome from retinacular compression produces burning plantar foot pain.
Maintains the medial ankle structures in their groove; the tarsal tunnel roof compresses the tibial nerve in tarsal tunnel syndrome
Tarsal tunnel syndrome from tibial nerve compression under the flexor retinaculum produces Tinel's sign over the medial ankle and burning plantar pain. Electrodiagnostic studies confirm slowed sensory nerve conduction velocity of the medial and lateral plantar branches. Surgical tarsal tunnel release with complete division of the retinaculum and individual compartment decompression resolves 85% of confirmed cases.
Tibial nerve compression under the flexor retinaculum producing burning plantar foot pain confirmed by Tinel's sign and nerve conduction study managed with surgical decompression.
