Tibial nerve (L4–S3)

Main branches · L4 L5 S1 S2 S3

Larger terminal division of the sciatic. Runs vertically through the popliteal fossa as the most superficial neurovascular structure, passes deep to the soleal arch with the posterior tibial vessels, descends between the superficial and deep posterior compartments and passes behind the medial malleolus in the tarsal tunnel to end as the medial and lateral plantar nerves.

Traced from the start

  1. L4 anterior ramusL5 anterior ramus
  2. S1 anterior ramusS2 anterior ramusS3 anterior ramusS4 anterior ramus
  3. Lumbosacral trunk (L4–L5)Sacral plexus anterior divisionsSacral plexus posterior divisions
  4. Sciatic nerve (L4–S3)
  5. Tibial nerve (L4–S3)

Detail

Motor
Gastrocnemius, soleus, plantaris, popliteus, tibialis posterior, flexor digitorum longus, flexor hallucis longus; intrinsic foot muscles via the plantar nerves
Sensory
Medial sural cutaneous nerve (to the sural), medial calcaneal branch (heel), sole via the plantar nerves
Tarsal tunnel, anterior to posterior
Tibialis posterior, flexor Digitorum longus, posterior tibial Artery, Vein, tibial Nerve, flexor Hallucis longus — Tom, Dick ANd Harry
Reflex
Ankle jerk (S1)

When it goes wrong

Tarsal tunnel syndrome: compression under the flexor retinaculum by a ganglion, tenosynovitis, pes planus or old fracture

Burning pain and paraesthesia in the sole and heel, worse at night and after standing, Tinel's sign behind the medial malleolus, late wasting of the intrinsic foot muscles

Injury in the popliteal fossa (knee dislocation, laceration) or high in the calf

Cannot plantarflex or stand on tiptoe, weak inversion and toe flexion, absent ankle jerk, numb sole, clawed toes from unopposed extensors

Practise this structure

1 question in the bank tagged Leg Compartments.