Gastrocnemius (medial head)

Musculus gastrocnemius, caput mediale

MuscularSuperficial musclesLegLeft and right

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What it is

The larger head of gastrocnemius, arising from the back of the medial femoral condyle. It forms the prominent inner bulge of the calf, extends lower than the lateral head and blends into the calcaneal (Achilles) tendon.

Function

Plantarflexes the ankle (push-off, standing on tiptoe) and flexes the knee.

Size

Belly about 20 cm long, 6-7 cm wide.

Clinical note

"Tennis leg" is a tear of its musculotendinous junction on the inner calf, typically in middle-aged recreational athletes.