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Gastrocnemius muscle

Plantarflexion is a movement required in jumping, running and walking. The gastrocnemius is a large muscle in the posterior compartment of the leg, and is the powerful muscle that enables plantarflexion, as well as knee flexion.

In this article we will discuss the anatomy of the gastrocnemius muscle, together with the clinical relevance of this muscle. 

Gastrocnemius muscle - dorsal view

Gastrocnemius muscle - dorsal view


Location & Relations

The leg consists of a posterior, anterior and lateral compartments. The posterior compartment, also known as flexor compartment, is divided into a deep and superficial components. The gastrocnemius is a large muscle in the superficial compartment and lies superficial to the soleus muscle. The plantaris muscle runs between both of them. There are four muscles that lie deep and form the deep flexor group,

  • popliteus
  • tibialis posterior
  • flexor hallucis longus
  • flexor digitorum longus
Recommended video: Posterior muscles of the leg
Origins, insertions, innervation and functions of the superficial and deep flexors.

Origins & Insertions

The gastrocnemius muscle is a large bipennate muscle that lies in the superficial part of the posterior compartment of the leg. The gastrocnemius has two heads. The lateral head arises from the lateral surface of the lateral femoral epicondyle, and the larger, medial head arises from the non-articular surface (upper and posterior part) of the medial femoral epicondyle behind the adductor tubercle and from the slightly raised area on the popliteal surface of femur shaft. Both heads also have their attachment from the capsule of the knee joint. There is present a bursa between each head and capsule of the knee joint.

Medial head of gastrocnemius muscle - axial view

Medial head of gastrocnemius muscle - axial view

The gastrocnemius muscle crosses the knee joint, and hence is also a weak flexor of the knee. The two heads of the muscle join into a broad aponeurosis, and will unite with the tendon of the soleus muscle, and insert onto the posterior surface of the calcaneus as the Achilles tendon. The Achilles tendon inserts onto the middle third of the calcaneus. Two bursae lie here at the site of insertion. The gastrocnemius lies superficial to the soleus muscle, which is also a plantar flexor of the ankle. Many anatomists consider the two heads of gastrocnemius and soleus to be the triceps surae of the leg.

Calcaneal tendon - medial view

Calcaneal tendon - medial view

The plantaris muscle lies superficial to gastrocnemius, and is a weak plantarflexor. It is considered to act in supporting the gastrocnemius. It arises above and lateral to the lateral head of the gastrocnemius, and descends in an inferomedial direction. The muscle occasionally inserts onto the calcaneus via a separate insertion, medial to the Achilles tendon.

Plantaris muscle - dorsal view

Plantaris muscle - dorsal view

The two heads of the gastrocnemius muscle form the inferior medial and lateral boundaries of the popliteal fossa in the upper part of the posterior leg. Almost the entire superficial surface of the muscle is covered by deep fascia over which lies the short saphenous vein. The common peroneal nerve passes posterior to the lateral head.

Small saphenous vein - dorsal view

Small saphenous vein - dorsal view

Blood Supply and Innervation

Both heads are supplied by medial and lateral sural arteries (branches of popliteal artery). The muscle is innervated by the tibial nerve (ventral rami of L4-S2), a branch of the sciatic nerve (ventral rami of L4-S3). The tibial nerve also supplies the posterior compartment of the thigh and leg (apart from the short head of biceps femoris, which is innervated by the common fibular nerve).

Sural arteries - dorsal view

Sural arteries - dorsal view


Gastrocnemius is a weak flexor of the knee joint and main plantar flexors along with soleus. The fleshy bellies of gastrocnemius provide rapid contraction necessary for propulsion during running, fast walk and jumping.

Recommended video: Functions of the gastrocnemius muscle
Functions and anatomy of the gastrocnemius muscle shown with 3D model animation.

Clinical Points

Tennis Leg

This is an injury that commonly occurs in tennis and squash players. It is sudden sharp pain at the back of the calf and usually follows rupture of the myotendinous junction of the medial head of the muscle, or rupture of the plantaris muscle (a less common cause).

Achilles Tendon Tendonitis

This is pain and thickening of the Achilles tendon at its insertion and most commonly occurs in middle and old age. The disease follows repetitive strain of the muscle that results in cartilaginous and bony metaplasia. The patient commonly presents with pain at the back of the heel and bony enlargement at the insertion of the tendon.

Achilles Tendon Rupture

This is often misdiagnosed as a simple ankle sprain and usually follows a sporting injury to the region. The rupture usually occurs 4-6cm above the calcaneal insertion of the tendon, which is relatively avascular. The patient may recall a pop sound upon rupturing of the tendon, and the feeling of the muscle rolling up their leg.

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Show references


  • Frank H.Netter MD: Atlas of Human Anatomy, 5th Edition, Elsevier Saunders.
  • Chummy S.Sinnatamby: Last’s Anatomy Regional and Applied, 12th Edition, Churchill Livingstone Elsevier.
  • Richard L. Drake, A. Wayne Vogl, Adam. W.M. Mitchell: Gray’s Anatomy for Students, 2nd Edition, Churchill Livingstone Elsevier.
  • Karadsheh M, MD: Achilles Tendon Rupture. Lineage Medical, LLC (accessed 04/03/2016).
  • Hatch D, MD: Achilles Tendonitis. Lineage Medical, LLC (accessed 04/03/2016).
  • Hacking C, MD and Jones J, MD: Gastrocnemius muscle. Radiopaedia.org (accessed 04/03/2016).
  • Luijkx T, MD and Prof Gaillard F, MD: Tennis leg. Radiopaedia.org (accessed 04/03/2016).

Author, Review and Layout:

  • Shahab Shahid
  • Uruj Zehra
  • Catarina Chaves


  • Gastrocnemius muscle - medial view - Liene Znotina
  • Calcaneal tendon - medial view - Paul Kim
  • Plantaris muscle - dorsal view - Liene Znotina
  • Small saphenous vein - dorsal view - Liene Znotina
  • Sural arteries - dorsal view - Liene Znotina
© Unless stated otherwise, all content, including illustrations are exclusive property of Kenhub GmbH, and are protected by German and international copyright laws. All rights reserved.

Related Atlas Images

Muscles of the leg and knee

Main muscles of the lower extremity

Soleus muscle level

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