leg

The leg, in human anatomy, refers to the portion of the lower limb between the knee and the ankle. It contains two bones, the tibia and the fibula, and is divided into compartments by fascia. The tibia bears most body weight; the fibula provides muscle attachment and stability. The leg forms the lower boundary of the thigh at the knee and connects to the foot at the ankle. The patella protects the knee extensor mechanism.

Muscles of the leg are arranged into anterior, posterior, and lateral compartments. The anterior group dorsiflexes the foot and extends the toes; major muscles include the tibialis anterior and extensor digitorum longus. The posterior group plantarflexes the foot and flexes the knee, with the gastrocnemius and soleus as primary muscles. The lateral group contains fibularis (peroneus) muscles that evert and plantarflex. Tendons and fascia support movement and link muscles to bone.

Innervation derives mainly from branches of the sciatic nerve: the tibial and common fibular nerves supply muscles and skin of the leg. Blood supply comes from the popliteal artery, which divides into the anterior and posterior tibial arteries. The deep venous system and perforating veins drain the leg.

Common injuries include fractures of the tibia or fibula, shin splints, and knee or ankle ligament injuries. The leg’s function is essential for standing, walking, and running. Treatment ranges from immobilization and physical therapy to surgical repair; orthotics and prosthetics support recovery and mobility.