Tibial Nerve

Question 1

Roots and sensory function?

Answer 1

Nerve roots: L4-S3

Sensory: Innervates the skin of the posterolateral side of the leg, lateral side of the foot, and the sole of the foot.

Question 2

Nerve course?

Answer 2

he tibial nerve is a branch of the sciatic nerve, and arises at the apex of the popliteal fossa. It travels through the popliteal fossa, giving off branches to muscles in the superficial posterior compartment of the leg. Here, the tibial nerve also gives rise to branches that contribute towards the sural nerve, which innervates the posterolateral aspect of the leg.

The tibial nerve continues its course down the leg, posterior to the tibia. During its descent, it supplies the deep muscles of the posterior leg.

At the foot, the nerve passes posteriorly and inferiorly to the medial malleolus, through a structure known as the tarsal tunnel. This tunnel is covered superiorly by the flexor retinaculum. Within this tunnel, branches arise from the tibial nerve to supply cutaneous innervation to the heel

Immediately distal to the tarsal tunnel, the tibial nerve terminates by dividing into sensory branches, which innervate the sole of the foot.

Question 3

Symptoms of tarsal tunnel syndrome?

Answer 3

Tarsal Tunnel Syndrome

This is a condition where the tibial nerve is compressed within the tarsal tunnel (posterior to the medial malleolus). There are varying causes, of which the main three are:

Osteoarthritis
Rheumatoid arthritis
Post-trauma ankle deformities
Patients complain of paraesthesia in the ankle and sole of the foot, which can radiate up the leg slightly. It is aggravated by activity and relieved by rest.

flexor retinaculum can be cut surgically, which releases the pressure.

Question 4

Sensory nerves? /Cutaneous branches.

Answer 4

In the popliteal fossa, the tibial nerve gives off cutaneous branches. These combine with branches from the common fibular nerve to form the sural nerve. This sensory nerve innervates the skin of the posterolateral side of the leg and the lateral side of the foot.

The tibial nerve also supplies all the sole of the foot via three branches:

Medial calcaneal branches: These arise within the tarsal tunnel, and innervate the skin over the heel.

Medial Plantar Nerve: Innervates the plantar surface of the medial three and a half digits, and the associated sole area.

Lateral Plantar Nerve: Innervates the plantar surface of the lateral one and a half digits, and the associated sole area.