Lateral Head of Gastrocnemius — Tendon

tendo musculi gastrocnemii lateralis

The lateral gastrocnemius head originates from the posterior lateral femoral condyle and has a more proximal musculotendinous junction than the medial head. It is less commonly the site of isolated tears. The lateral gastrocnemius muscle flap provides coverage for lateral proximal tibial defects. A fabella (sesamoid in the lateral gastrocnemius tendon) is present in 10-30% of individuals and can cause posterolateral knee pain.

Region: Lower Leg

Biomechanics

Function & Actions

Ankle plantarflexion; contributes less force than the medial head due to smaller cross-sectional area

Clinical Relevance

Clinical Notes

The fabella (sesamoid bone in the lateral gastrocnemius proximal tendon) is a normal variant present in 10-30% of the population. It can produce posterolateral knee pain (fabella syndrome) from impingement against the lateral femoral condyle. Symptomatic fabella is treated with local injection and, rarely, surgical excision.

Pathology

Common Injuries & Conditions

Fabella Syndrome

Sesamoid bone in the lateral gastrocnemius origin impinging against the lateral femoral condyle producing posterolateral knee pain managed with injection and fabella excision for refractory cases.