Lower Leg Muscles
The leg muscles can be broken into two groups, the upper leg muscles and the lower leg muscles.The upper and lower leg muscles can be further divided into anterior (front) and posterior (back) of leg muscles.
The primary front leg muscles, also called the thigh muscles, are the four muscles of the quadriceps femoris. These are the vastus intermedius, vastus medialis, vastus lateralis, and rectus femoris. These muscles are responsible for extending or straightening the leg.
The muscles at the back of the upper leg are often called the hamstrings. These muscles include the biceps femoris, semitendinosus and semimembranosus. These muscles are responsible for flexing or bending the leg at the knee.
Sometimes the gluteus maximus, or "butt" muscles, running from the pelvis to the upper thigh are also considered leg muscles.
In the lower leg, the front of the shin has the tibilais anterior, extensor digitorum longus, extensor hallucus longus and peroneus tertius muscles. The shin muscles are responsible for dorsiflexion of the foot, or bending the foot upwards at the ankle. The outside lower leg contains the peroneus longus and peroneus brevis muscles. The are responsible for sideways flexion and extension of the foot at the ankle. The provide lateral stability to the foot. The back of the lower leg includes the calf muscles which are the gastrocnemius, soleus, and plantaris muscles. The calf muscles pull up the heel, and extend the foot, during the "push-off" phase of walking and running.