Lower limb
Achilles tendon
Tendo calcaneus (tendo Achillis)
- Origin
- Common tendon of the medial and lateral heads of gastrocnemius (femoral condyles) and soleus (tibia, fibula, soleal line)
- Insertion
- Calcaneal tuberosity (posterior surface of the heel bone)
- Function
- Transmits the force of triceps surae for plantarflexion of the ankle; essential for push-off in walking, jumping and running
- Innervation
- Tibial nerve, S1-S2
- Movement & chain
- Transfers tensile loads from triceps surae (gastrocnemius and soleus) to the calcaneus for explosive plantarflexion in gait and jumping.
- Palpation
- Readily palpable as a firm cord-like structure between heel and calf, especially taut during resisted active plantarflexion.
- Clinical
- Frequent site of tendinopathy (Achilles tendon complaints) in runners; an acute Achilles tendon rupture often produces an audible 'pop' with sudden loss of function (positive Thompson test).
- Segmental innervation
- S1–S2 (tibial nerve)
- In clinical practice
- When rupture is suspected, the calf is squeezed (Thompson test): absence of plantarflexion indicates a torn tendon.
- Region in the model
- Lower limb