Muscle
Gastrocnemius
Two-headed calf muscle linking the knee and heel
High-yield
Gastrocnemius and soleus form the triceps surae. Both provide ankle plantarflexion, but only gastrocnemius crosses the knee, so knee position changes its length and contribution to movement.
Overview
Gastrocnemius forms much of the visible calf contour. Its two heads arise near the femoral condyles and join the heel through the Achilles tendon, allowing it to act at both the knee and ankle.
Reference facts
- Origin
- Posterior distal femur around the medial and lateral condyles, with two separate heads
- Insertion
- Posterior calcaneus through the shared calcaneal, or Achilles, tendon
- Action
- Pushes the foot downward at the ankle and assists knee flexion
- Innervation
- Tibial nerve muscular branches, chiefly S1-S2
- Blood supply
- Sural branches arising from the popliteal artery
Clinical correlation
A medial gastrocnemius tear is one cause of sudden calf pain called tennis leg. Similar symptoms can come from other muscle injuries or deep vein thrombosis, so this label does not establish the cause.
Frequently asked questions
What does the gastrocnemius do?
The gastrocnemius pushes the foot downward at the ankle and assists knee flexion.
What nerve innervates the gastrocnemius?
The gastrocnemius is innervated by the tibial nerve muscular branches, chiefly S1-S2.
Where does the gastrocnemius attach?
Origin: Posterior distal femur around the medial and lateral condyles, with two separate heads. Insertion: Posterior calcaneus through the shared calcaneal, or Achilles, tendon.
What is the blood supply of the gastrocnemius?
The gastrocnemius is supplied by the sural branches arising from the popliteal artery.