Human leg the anterior superior iliac spine to the pes anserinus on the medial side of the knee, from where it is further extended into the crural fascia. The sartorius acts as a flexor on both the hip and knee, but, due to its oblique course, also contributes to medial rotation of the leg as one of the pes anserinus muscles (with the knee flexed), and to lateral rotation of the hip joint. There are four posterior thigh muscles. The biceps femoris has two heads: The long head has its origin on the ischial tuberosity together with the semitendinosus and acts on
Gastrocnemius muscle Gastrocnemius muscle The gastrocnemius muscle (plural "gastrocnemii") is a superficial two-headed muscle that is in the back part of the lower leg of humans. It runs from its two heads just above the knee to the heel, a two joint muscle. The muscle is named via Latin, from Greek "γαστήρ" ("gaster") "stomach" and "κνήμη" ("knḗmē") "leg"; meaning "stomach of leg" (referring to the bulging shape of the calf). The gastrocnemius is located with the soleus in the posterior (back) compartment of the leg. The lateral head originates from the lateral condyle of the femur, while the medial head originates from