The lateral gastrocnemius head originates from the posterior lateral femoral condyle and is slightly smaller and higher than the medial head. Its posterolateral origin is relevant in gastrocnemius equinus assessment and in lateral gastrocnemius recession for spasticity. The tendinous origin contains the fabella (sesamoid bone) in approximately 25% of individuals.
| Origin | Posterior lateral femoral condyle (above the articular surface) |
|---|---|
| Insertion | Converges with medial head into the Achilles tendon via gastrocnemius tendon |
| Nerve Supply | Tibial nerve S1, S2 — nerve to lateral head of gastrocnemius |
| Blood Supply | Sural arteries (popliteal branches) |
| Actions | Plantarflexes the ankle; Flexes the knee; Provides energy storage in the gastrocnemius spring mechanism during running |
|---|
The lateral gastrocnemius head is individually released in selective gastrocnemius recession for equinus deformity in cerebral palsy and for isolated gastrocnemius tightness (Silfverskiöld test). The Strayer procedure releases both heads at the musculotendinous junction, while selective medial or lateral release targets individual heads. EMG of the lateral head separately from the medial head guides botulinum toxin injection for spastic equinus.
Palpable as the lateral bulge of the calf with the knee extended during active ankle plantarflexion.
Selective lateral gastrocnemius recession for isolated lateral gastrocnemius contracture contributing to equinus valgus foot posture, released at the musculotendinous junction by the Strayer or Baker procedure.
