The tarsal tunnel is the space located posterior and inferior to the medial malleolus, lateral to the calcaneus and talus, and medial to the flexor retinaculum. Many structures run through the tarsal tunnel, including, from anterior to posterior, the tibialis posterior tendon, the flexor digitorum longus tendon, the posterior tibial artery, tibial nerve, and flexor hallucis longus.


Tenderness of the tarsal tunnel is a sign of tarsal tunnel syndrome. Tarsal tunnel syndrome refers to compression of the posterior tibial nerve. Compression of the posterior tibial nerve has many etiologies, but in most cases the cause is unknown.

Post-traumatic swelling is one possible explanation for the neuropathy. A space occupying lesion, such as a ganglion cyst, swollen tendon, varicosity, or bone spur, could also compress the posterior tibial nerve in the confined space of the tarsal tunnel. Ankle deformities and pes planus can contribute to tarsal tunnel syndrome as well. Complex regional pain syndrome should be considered if there is regional discoloration, swelling, temperature changes, allodynia, or hyperesthesia present. If the pain has a stocking distribution, a diabetic or peripheral neuropathy may be the cause. Also, if there is leg and thigh pain accompanying the tarsal tunnel symptoms, a herniated lumbar disk should be considered.