Gastrocnemius
Leg & Ankle
The 'calf muscle' everyone sees — it's the power behind pushing off when you walk, run, or jump.
Function
Plantarflexes ankle, assists knee flexion
Origin
Medial head: medial femoral condyle; Lateral head: lateral femoral condyle
Insertion
Calcaneus via Achilles tendon
Innervation
Tibial nerve (S1-S2)