MuscleLeg — posterior superficial
Gastrocnemius
Latin: M. gastrocnemius sinistra
Location: Leg
Paired structure: one on the left and one on the right side of the body.
View the gastrocnemius in 3DOrigin
Lateral head: lateral femoral condyle. Medial head: medial femoral condyle (just above the epicondyle).
Insertion
Calcaneal (Achilles) tendon into the posterior calcaneus.
Action
Plantarflexes the ankle with explosive force — the jumping muscle; also flexes the knee and, via the Achilles tendon's elastic recoil, returns running energy.
Nerve supply
Tibial nerve (S1–S2).
Blood supply
Sural arteries from the popliteal.
Clinical relevance
Medial-head gastrocnemius tears — 'tennis leg' — mimic deep vein thrombosis; a snapped Achilles tendon loses plantarflexion with a palpable gap and positive Thompson test.
Educational anatomy reference, not medical advice. About this content.