where is your gastrocnemius muscle
1 Activate Your Free Trial!  Gastrocnemius muscle. Gastrocnemius muscle, also called leg triceps, large posterior muscle of the calf of the leg. It originates at the back of the femur (thighbone) and patella (kneecap) and, joining the soleus (another muscle of the calf), is attached to the Achilles tendon at the heel.