Corpus: Tibial nerve

The tibial nerve arises from the sciatic nerve, which is part of the sacral plexus. It carries both somatomotor and general somatosensory fibers originating from spinal cord segments L4 to S3.

The tibial nerve begins on the dorsal, distal side of the thigh, branching from the sciatic nerve. It lies superficially in the popliteal fossa and continues distally between the deep flexors and the soleus muscle, accompanying the tibial vessels within the deep flexor compartment of the lower leg. The nerve travels through the malleolar canal to the plantar side of the foot, where it divides into its terminal branches: the medial and lateral plantar nerves.

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3.1. Interosseous crural nerve

Originating in the popliteal fossa, the interosseous crural nerve extends to the crural interosseous membrane and the tibiofibular syndesmosis, providing sensation to the talocrural joint.

3.2. Medial sural cutaneous nerve

The medial sural cutaneous nerve provides sensory input to the dorsal skin of the lower leg and merges with the lateral cutaneous nerve from the common fibular nerve to form the sural nerve.

3.3. Muscular branches

The tibial nerve's muscular branches innervate nearly all the dorsal muscles of the lower extremity, including:

• Portions of the adductor magnus muscle

Flexors at the knee joint:

• Biceps femoris (long head)
• Semimembranosus muscle
• Semitendinosus muscle
• Popliteus muscle

Flexors at the ankle joints:

• Triceps surae
• Flexor hallucis longus muscle
• Tibialis posterior muscle
• Flexor digitorum longus muscle
• Plantaris muscle

3.4. Articular branches

These branches supply sensation to the knee joint.

3.5. Medial calcaneal branches

These branches provide sensitive innervation to the skin over the heel.

3.6. Medial plantar nerve

The medial plantar nerve provides sensory and motor functions to the sole of the foot, innervating:

• Abductor hallucis muscle
• Flexor hallucis brevis muscle (medial head)
• First and second lumbricals
• Flexor digitorum brevis muscle

3.7. Lateral plantar nerve

The lateral plantar nerve serves the skin and muscles of the sole, innervating:

• Abductor digiti minimi muscle
• Quadratus plantae muscle
• Flexor hallucis brevis muscle (lateral head)
• Flexor digiti minimi brevis muscle
• Adductor hallucis muscle
• Opponens digiti minimi muscle
• Third and fourth lumbricals
• Plantar and dorsal interossei muscles

Total damage to the tibial nerve results in loss of function in the supinators and flexors of the lower leg, making toe walking difficult or impossible. The foot adopts a pronated and dorsiflexed position, commonly referred to as "heel foot."

Compression of the tibial nerve or its terminal branches at the malleolar canal can lead to medial tarsal tunnel syndrome, characterized by pain and sensory disturbances in the sole of the foot. Occasionally, this may also cause paresis of the short foot muscles.

• Waldeyer et al. Anatomie des Menschen: Lehrbuch und Atlas in einem Band (De Gruyter Studium) (19th totaly rev. ed.), De Gruyter, 2012
• Waldeyer et al. Anatomie des Menschen: Lehrbuch und Atlas in einem Band (De Gruyter Studium) (19th totaly rev. ed.), De Gruyter, 2012
• Aumüller et al. Duale Reihe Anatomie: Mit Online-Zugang (5. aktualisierte Aufl.), Thieme, 2020