Lowerlimb

The lower limb refers to the part of the body from the pelvis to the foot that is specialized for weight bearing and locomotion. It is organized into three main segments—the thigh, leg, and foot—and is connected to the trunk by the hip joint. The primary joints include the hip, knee, and ankle, with numerous articulations within the foot that contribute to balance and propulsion.

Bones form the framework of the lower limb. The thigh contains the femur, the leg contains the tibia and fibula, and the foot comprises the tarsals, metatarsals, and phalanges, with the calcaneus (heel bone) playing a key role in weight transfer. Joints such as the hip (acetabulum and femoral head), knee (femur–tibia with the patella), and ankle (tibia–fibula–talus) enable a wide range of movements, while many smaller joints in the foot provide adaptability on uneven surfaces.

Muscles and compartments support movement and stability. The thigh has anterior, posterior, and medial compartments with muscles like the quadriceps and hamstrings. The leg is divided into anterior, lateral, and posterior compartments, containing muscles such as the tibialis anterior and the gastrocnemius–soleus group. These muscles act across the hip, knee, and ankle to produce flexion, extension, rotation, and plantar or dorsiflexion.

Nerve and blood supply are essential for function. The femoral nerve supplies the anterior thigh, while the sciatic nerve (and its tibial and common fibular branches) innervates the posterior thigh and leg. The arterial supply runs from the femoral artery to the popliteal, then anterior and posterior tibial arteries, with venous return via deep veins to the external iliac system.

Clinically, the lower limb is a common site of injury and disease, including fractures, ligament injuries, vascular disorders, and compartment syndrome. Anatomical variation, such as limb length discrepancy, can affect gait and function.