The musculature of the legs is composed of several muscle groups, explains Folsom Lake College. These include the gastrocnemius and soleus, located in the calf area; the gluteus, found in the buttocks; the quadriceps, located at the anterior thigh; and the hamstrings, found at the posterior of the thighs.
The gluteus maximus is the body's strongest muscle and stretches over a significant proportion of the buttocks, notes Inner Body. The muscle links the thigh bone to the coccyx, ilium and sacrum. Among other functions, the gluteus maximus extends legs at the hip during climbing, running or walking and also helps the body rise from a sitting position.
The gluteus maximus partially covers the gluteus medius, explains Inner Body. Stretching from the thigh bone to the ilium, the gluteus medius muscles move the thighs out or rotate them medially. To accomplish these movements, the gluteus medius are assisted by the underlying gluteus minimus muscles.
The gastrocnemius muscle is composed of two heads; the medial and the lateral, reports Inner Body. Both heads connect to the thigh bone; the medial to its center, and the lateral to its side. The other side of the gastrocnemius attaches to the Achilles tendon, which in turn connects to the calcaneus at the heel. The gastrocnemius bends the legs at the knees and also helps propel the body forward in running and walking.