Gastrocnemius Anatomy

Gastrocnemius Muscle

Origin:  Medial head: Posterior part of the medial condyle and the adjoining part of the femur.
Lateral head: The lateral condyle and the adjoining part of the femur.
Insertion:  The calcaneus via the Achilles tendon
Actions: Plantarflexion of the foot at the ankle, assists with flexion of the leg at the knee
Innervation: Tibial nerve S1, S2
Blood Supply: Branches from the posterior tibial and popliteal arteries

Primary Actions of the Gastrocnemius Muscle

1. Plantarflexion of the foot at the ankle

Agonists:

  • Soleus

  Antagonists:

  • Tibialis Anterior

Plantaris, tibialis posterior, peroneus longus, flexor hallucis longus, and flexor digitorum longus assist with plantarflexion of the foot at the ankle.

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Secondary Actions of the Gastrocnemius Muscle

2. Assists with flexion of the leg at the knee

Agonists:

  • Biceps Femoris
  • Semitendinosus
  • Semimembranosus

  Antagonists:

  • Vastus Lateralis
  • Vastus Medialis
  • Vastus Intermedius
  • Rectus Femoris

Gracilis, sartorius, popliteus, and plantaris also assist with flexion of the knee.