Lower limb
Lateral head of gastrocnemius
Caput laterale musculi gastrocnemii
- Origin
- Lateral condyle of the femur
- Insertion
- Calcaneus, via the Achilles tendon
- Function
- Plantarflexion of the foot and flexion of the knee
- Innervation
- Tibial nerve, S1-S2
- Movement & chain
- Together with the medial head and soleus, forms the calf muscle group (triceps surae), essential for push-off in walking, jumping and running; as a two-joint muscle its force output depends on knee angle.
- Palpation
- Together with the medial head, forms the visible contour of the calf; readily palpable during active plantarflexion with the knee extended (for example standing on the toes).
- Clinical
- Often involved in 'tennis leg', an acute tear at the myotendinous junction, usually of the medial head but also occurring laterally.
- Segmental innervation
- S1-S2, part of the reflex arc of the Achilles tendon reflex.
- In clinical practice
- Triceps surae (including this head) is tested via the Achilles tendon reflex (S1) and by standing on the toes as a functional strength screen.
- Region in the model
- Lower limb