Tibial Nerve

Original Editor - Lucinda hampton

Top Contributors - Lucinda hampton, Leana Louw, Nehal Shah and Rucha Gadgil

Description

The tibial nerve is the larger terminal branch of the two main muscular branches of the sciatic nerve.It arises from Ventral (anterior) division of L4-5, S1-3. It travels along the distal border of the popliteus muscle, deep to gastrocnemius and soleus. In the leg, it is accompanied by the posterior tibial vessels and lies in the tarsal tunnel.

The tibial nerve provides innervation to the muscles of the lower leg and foot. Specifically: triceps surae (the two headed gastocnemius and soleus), plantaris, Popliteus, tibialis posterior, flexor digitorum longus and flexor hallucis longus. It also has articular and cutaneous branches.

Nerve Root of origin

Anterior parts of the L4-S3 rami.

Course of the nerve and Branches

Tibial nerve passes from the posterior aspect of the thigh and the popliteal fossa to the distal border of the popliteus muscle. It further passes deep to gastrocnemius and soleus muscles, and then anterior to the arch of soleus muscle with the popliteal artery. In the leg, the tibial nerve travels with posterior tibial vessels and lies in a fibro-osseous tunnel called the tarsal tunnel. Medially tarsal tunnel is bounded by the flexor retinaculum, laterally by the posterior aspect of talus and calcaneum, and anteriorly by the medial malleolus.

There are three main branches of Tibial nerve

• Medial Calcaneal Nerve - It arises in the ankle, traverses the flexor retinaculum and supplies posterior and lower aspect of the heel. It is a sensory nerve.
• Medial and Lateral Planter nerves - In the tarsal tunnel, Tibial nerve gives two branches - the Medial Planter Nerve (MPN) and Lateral Planter nerves (LPN). The MPN supplies muscular branches to the big toe and the two toes next to it, and the LPN the other two toes.
• Sural Nerve - The sural nerve is a cutaneous branch of the tibial nerve that supplies the skin of the legs and feet.

Anatomical Variation of Tibial Nerve Bifurcation

In the tarsal tunnel where the Tibial nerve bifurcates into the MPN and LPN, studies have found out various branching points within the Tarsal tunnel.

Malleolar-calcaneal axis (MCA) is the axis extending from medial malleolus to the medial calcaneal tuberosity. It is a reference line for classification of branching points. Based on MCA, following are the types of tibial nerve branching points

• Type I- branches above the axis and within the tarsal tunnel
• Type II - branches as high as the axis
• Type III - branches at the distal end of the axis and within the tarsal tunnel
• Type IV - branches at the proximal axis and outside the tarsal tunnel
• Type V - branches at the distal axis and outside the tarsal tunnel

Function

Motor

• At the popliteal fossa, branches of the tibial nerve supply medial and lateral heads of gastrocnemius, soleus, plantaris and popliteus muscles. The popliteus branch goes on to supply tibialis posterior muscle, superior and inferior tibiofibular joint, tibiaand the interosseous membrane of leg.
• Posterior branches of the tibial nerve supply tibialis posterior, flexor digitorum longus, flexor hallucis longus, and deep part of soleus.

Sensory

Branches of the tibial nerve supply sensory innervation to the following:

• Medial sural nerve supplies skin on lower half back of leg and skin of foot laterally to the little toe.
• Medial calcaneal nerve supplies skin on posterior and inferior surface calcaneus.
• Articular branches are to the knee (3 in total) and ankle joint.

Clinical relevance

Injury to the tibial nerve can cause motor loss and altered sensation and pain to any of the areas it supplies, depending on site of involvement.

1. Popliteal fossa region. Injury may occur due to e.g.:
   • Space occupying lesion
   • Laceration injury
   • Posterior dislocation of the knee
   • Entrapment in soleus arch: Soleus arch entrapment neuropathy can occur with sports that make special demands on the calf muscles. Swelling and hypertrophy of the soleus muscle may cause its tendinous arch to compress the popliteal artery and vein as well as the tibial nerve. This can cause chronic mechanical damage to the nerve and the artery and vein may become occluded. This is requires surgical release and has a good outcome.
   • Fractures of the tibia and fibula.
   • Local trauma to the posterior lower leg.
2. Medial malleolus level:
   • Compression of the tibial nerve in the osseofibrous tunnel below the flexor retinaculum of the ankle causes tarsal tunnel syndrome. On examination it presents as pain and paresthesia in the sole of the foot.
   • Tibial nerve block done for certain operations of the foot.
3. Sole of foot:
   • Abnormal pressure at the ball of the foot can irritate the first plantar digital nerve causing Morton's neuroma/Metatarsalgia.

Assessment and Treatment

For more details on the assessment and management of conditions mentioned above, see the following pages:

• Tarsal Tunnel Syndrome
• Morton's Neuroma/Metatarsalgia.

Entrapment in soleus arch

Physiotherapy post surgical release would include:

• Neural mobilisation (e.g. flossing techniques)
• Strengthening and muscle flexibility graded exercises
• Coordination and balance training
• Electrotherapeutic techniques (e.g. TENS) or heat may be used for pain relief.

The video below gives a good overview of the nerve and use of flossing techniques for the tibial nerve