Anatomy:
Fibro-osseous canal bounded by flexor retinaculum superficially and medial surfaces of talus and calcaneus on deep surface
Contains posterior tibial nerve, medial tendons (TDH), posterior tibial artery and vein
In most, posterior tibial nerve divides into medial and lateral plantar nerves within tarsal tunnel
Medial calcaneal nerve is variable and can arise directly from posterior tibial nerve or lateral plantar nerve, occasionally with multiple branches.
Syndrome:
Entrapment neuropathy of posterior tibial nerve or of its branches within tarsal tunnel
Clinically present with pain and paresthesias in toes, sole, or heel
On examination, Tinel sign (distal paresthesia produced by percussion over nerve) may be positive
Electromyography and nerve conduction studies are useful
Abnormalities:
Bone deformity after calcaneal fractures
Varicosities
Tenosynovitis of flexor tendons
Tumors or tumorlike lesions
Accessory or hypertrophied abductor hallucis muscle
Synovial hypertrophy
References:
Narváez JA et al. Painful heel: MR imaging findings. Radiographics. 2000;20:333-352
Further links:
Tarsal_tunnel_syndrome (Wikipedia)
Tarsal tunnel syndrome (RadSource)
Tarsal tunnel syndrome (eMedicine)
Tight spaces and tunnels
Tarsal tunnel syndrome: wheelessonline
