legs

The legs are the paired limbs that extend from the pelvis to the feet and play a central role in bearing the body's weight, maintaining balance, and enabling locomotion. In humans, the leg is typically described as the thigh, the leg proper (between knee and ankle), and the foot.

Anatomy and features include bones, joints, muscles, tendons, nerves, and vessels. Major bones are the femur, patella, tibia, fibula, and the bones of the foot (tarsals, metatarsals, and phalanges). Key joints are the hip, knee, and ankle, along with numerous foot joints. The muscular system includes the quadriceps and hamstrings in the thigh, the gastrocnemius and soleus in the calf, and various muscles controlling toe and ankle movement. Tendons such as the patellar tendon and the Achilles tendon transmit forces between bones and muscles. The legs are supplied by the femoral and popliteal arteries, with innervation from the femoral, sciatic, and other nerves.

Functionally, the legs provide support, absorb impact during weight bearing, and generate propulsion for gait. Locomotion involves coordinated phases of stance and swing, with power largely produced by the hip extensors, knee extensors, and ankle plantarflexors. Effective leg function depends on alignment, muscular strength, flexibility, and circulatory health.

Variation exists across individuals and species. Humans are adapted to bipedal locomotion, with an arched foot and non-opposable big toe contributing to efficient propulsion. Leg health can be affected by fractures, ligament injuries, osteoarthritis, and circulatory disorders, among other conditions.