Major Muscles of the Posterior Compartment of the Leg

Gastrocnemius Muscle - Origin, Insertion, Nerve Supply, and Function

The gastrocnemius muscle is a vital component of the posterior compartment of the leg. It is responsible for movements essential to walking, running, and jumping.

Origin

• The gastrocnemius muscle has two heads: medial and lateral.
• Medial head: originates from the posterior surface of the medial femoral condyle.
• Lateral head: originates from the posterior surface of the lateral femoral condyle.

Insertion

The muscle inserts into the posterior surface of the calcaneus via the Achilles tendon, forming a crucial structure for plantar flexion.

Nerve Supply

The gastrocnemius muscle is innervated by the tibial nerve (S1, S2), allowing effective contraction and relaxation.

Function

• Primary function: plantar flexion of the foot at the ankle joint.
• Assists in knee flexion.
• Provides stability during walking and running.