Overview
This lecture covers the anatomy, attachments, functions, nerve supply, and blood supply of the gastrocnemius (calf) muscle.
Anatomy of the Gastrocnemius
- The gastrocnemius muscle is a strong, superficial muscle in the posterior compartment of the leg.
- It forms the superficial posterior compartment together with the soleus and plantaris muscles.
- The muscle has two heads: medial and lateral.
Attachments and Structure
- The medial head attaches to the posterior part of the medial femoral condyle.
- The lateral head attaches to the posterior part of the lateral femoral condyle.
- Both heads join with soleus and plantaris via the calcaneal tendon.
- The calcaneal tendon inserts on the posterior surface of the calcaneus (heel bone).
Actions and Functions
- Main action: plantar flexion of the foot at the ankle joint.
- Assists in knee flexion since it crosses the knee joint.
Nerve and Blood Supply
- The gastrocnemius is innervated by the tibial nerve (a branch of the sciatic nerve).
- The tibial nerve runs between the two heads of gastrocnemius and around the medial ankle.
- Blood supply is from the popliteal artery, a continuation of the superficial femoral artery.
- Popliteal artery gives off sural branches, which supply the gastrocnemius.
Key Terms & Definitions
- Gastrocnemius — Superficial calf muscle in the posterior leg, responsible for plantar flexion.
- Calcaneal tendon — Strong tendon (Achilles) anchoring calf muscles to the heel bone.
- Tibial nerve — Nerve supplying the posterior leg muscles; branch of the sciatic nerve.
- Popliteal artery — Main artery behind the knee, supplying blood to lower leg muscles.
- Sural branches — Small branches from the popliteal artery that supply the calf muscle.
Action Items / Next Steps
- Watch the next video on gastrocnemius injury and rehabilitation.