A Rare Case of Flexor Digitorum Accessorius Longus Muscle Presenting as Tarsal Tunnel Syndrome.

Tarsal tunnel syndrome (TTS) is a relatively uncommon nerve entrapment neuropathy. Many pathologies are reported as possible causes for TTS. The diagnosis of TTS can be difficult and often missed. We present a rare case of TTS due to an accessory flexor digitorum longus muscle. Together with a high index of suspicion, MRI is the investigation of choice in making the diagnosis. These patients are best managed with excision or transposition of the flexor digitorum accessorius longus (FDAL) and neurolysis of the posterior tibial nerve and its branches.