Lower limb
Medial head of gastrocnemius
Musculus gastrocnemius, caput mediale
- Origin
- Posterior surface of the medial femoral condyle, just above the knee joint
- Insertion
- Calcaneus, via the common Achilles tendon (together with the lateral head and soleus)
- Function
- Plantarflexion of the ankle and flexion of the knee; the major contributor to triceps surae
- Innervation
- Tibial nerve (S1-S2)
- Movement & chain
- Works mainly eccentrically during the stance phase of walking and concentrically during push-off; the medial head is larger and more powerful than the lateral head.
- Palpation
- The medial belly is clearly visible and palpable on the medial side of the calf, distal to the knee crease.
- Clinical
- A sudden, forceful load (for example sprinting or push-off) can cause a muscle tear of the medial head, known as 'tennis leg', with acute calf pain.
- Segmental innervation
- S1-S2, part of the reflex arc of the Achilles tendon reflex.
- In clinical practice
- Calf pain from an acute tear of this head must be considered in the differential diagnosis alongside deep vein thrombosis (DVT).
- Region in the model
- Lower limb