The tibial nerve descends through the popliteal fossa between the two heads of gastrocnemius, passes deep to the soleus at the tendinous arch, and runs with the posterior tibial artery through the deep posterior compartment to the tarsal tunnel. It supplies gastrocnemius, soleus, plantaris, popliteus, tibialis posterior, flexor digitorum longus, and flexor hallucis longus before dividing at the ankle into medial and lateral plantar nerves.
| Origin | Sciatic nerve (L4, L5, S1, S2, S3) |
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| Course | Descends through the centre of the popliteal fossa superficial to the popliteal vessels and between the heads of gastrocnemius, passes deep to the tendinous arch of soleus, runs with the posterior tibial vessels on tibialis posterior, and passes behind the medial malleolus in the tarsal tunnel (between the tendons of flexor digitorum longus and flexor hallucis longus) to divide, usually under the flexor retinaculum, into the medial and lateral plantar nerves |
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| Sensory |
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In the popliteal fossa the tibial nerve is relatively protected by its central position, but it can be injured in knee dislocation (less often than the common fibular nerve), by direct trauma, or compressed by a ruptured popliteal cyst or popliteal artery aneurysm. Tibial nerve palsy causes loss of plantarflexion and toe flexion and a numb sole that is at high risk of pressure ulcers, so careful foot care and padding are essential. Tarsal tunnel syndrome is compression of the nerve or its plantar branches under the flexor retinaculum at the medial ankle; the symptoms depend on whether the main trunk, the medial or lateral plantar nerve or the calcaneal branches are involved. A Tinel sign at the tarsal tunnel and plantar nerve conduction studies help confirm it.
Complete tibial nerve injury producing loss of plantarflexion, intrinsic foot muscle paralysis, and plantar sensory loss, resulting in a calcaneovalgus deformity and neuropathic ulceration at pressure points.
Tibial nerve compression under the flexor retinaculum producing plantar burning, Tinel sign at the medial ankle, and intrinsic foot weakness, managed by decompression when conservative treatment fails.
