Human Anatomy
Back of the Leg and Sole of the Foot
Back of the leg and sole anatomy for MBBS: calf muscles, tibial nerve, tarsal tunnel, plantar nerves and arches of the foot, mapped to NMC codes AN19.1 to AN19.7.
MedNext Academy | 3 min read
Back of the Leg and Sole of the Foot
Back of the leg and sole anatomy for MBBS: calf muscles, tibial nerve, tarsal tunnel, plantar nerves and arches of the foot, mapped to NMC codes AN19.1 to AN19.7.
This chapter covers the back of the leg and the sole of the foot, the calf muscles that power push-off and the intrinsic muscles and arches of the sole. It details the superficial and deep flexor groups, the tibial nerve and its plantar branches, and the tarsal tunnel behind the medial malleolus.
High-yield: Back of the Leg and Sole of the Foot
- The posterior compartment of the leg is divided into superficial and deep groups by the transverse intermuscular septum.
- The superficial group is gastrocnemius, soleus and plantaris, which together form the tendo calcaneus.
- Gastrocnemius and soleus plantarflex the ankle and are supplied by the tibial nerve.
- The tendo calcaneus, or Achilles tendon, is the strongest tendon in the body and inserts into the calcaneus.
- The deep group includes tibialis posterior, flexor digitorum longus and flexor hallucis longus.
- Tibialis posterior inverts the foot and supports the medial longitudinal arch.
- The tibial nerve and posterior tibial vessels pass behind the medial malleolus deep to the flexor retinaculum.
- The tarsal tunnel behind the medial malleolus transmits, from front to back, tibialis posterior, flexor digitorum longus, the vessels and tibial nerve, and flexor hallucis longus.
- The posterior tibial pulse is felt midway between the medial malleolus and the heel.
- The tibial nerve divides into the medial and lateral plantar nerves in the sole.
- The medial plantar nerve is the equivalent of the median nerve of the hand and supplies most of the medial sole muscles.
- The lateral plantar nerve is the equivalent of the ulnar nerve and supplies most of the small muscles of the sole.
- The plantar aponeurosis supports the longitudinal arches of the foot.
- The sole has four muscle layers and its arches are maintained by bones, ligaments, muscles and the plantar aponeurosis.
Posterior leg muscle groups
- **Superficial group:** Gastrocnemius, soleus, plantaris; plantarflex the ankle through the tendo calcaneus; tibial nerve.
- **Deep group:** Tibialis posterior, flexor digitorum longus, flexor hallucis longus; invert the foot and flex the toes.
- **Tibial nerve:** Runs behind the medial malleolus in the tarsal tunnel and divides into medial and lateral plantar nerves.
- **Plantar nerves:** Medial plantar (like the median) and lateral plantar (like the ulnar) supply the sole muscles.
NMC competencies in this chapter
- **AN19.1:** Superficial muscles of the back of the leg
- **AN19.2:** Deep muscles of the back of the leg
- **AN19.3:** Course and relations of the tibial nerve
- **AN19.4:** Posterior tibial artery and its branches
- **AN19.5:** Flexor retinaculum and tarsal tunnel
- **AN19.6:** Muscles, nerves and vessels of the sole of the foot
- **AN19.7:** Arches of the foot and applied anatomy
Frequently Asked Questions
What passes through the tarsal tunnel?
Behind the medial malleolus, deep to the flexor retinaculum, the tarsal tunnel transmits, from front to back, tibialis posterior, flexor digitorum longus, the posterior tibial vessels and tibial nerve, and flexor hallucis longus.
What forms the tendo calcaneus?
The tendons of gastrocnemius and soleus, sometimes with plantaris, unite to form the tendo calcaneus, or Achilles tendon, which inserts into the back of the calcaneus and plantarflexes the ankle.
How is the tibial nerve like the median and ulnar nerves?
In the sole the tibial nerve divides into the medial plantar nerve, comparable to the median nerve of the hand, and the lateral plantar nerve, comparable to the ulnar nerve, with similar muscle distributions.
How are the arches of the foot maintained?
The arches are supported by the shape of the bones, the plantar ligaments, the plantar aponeurosis and the pull of the intrinsic and long tendons, which together act as a springy, weight-distributing structure.
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