Lowerextremity

Lower extremity refers to the part of the body from the hip to the foot, commonly described as the thigh, the leg, and the foot. The major bones include the femur in the thigh; the tibia and fibula in the leg; and the tarsals, metatarsals, and phalanges in the foot. The joints span the hip, knee, and ankle, with numerous joints in the foot such as the subtalar and metatarsophalangeal joints.

Muscle groups are organized into compartments that provide movement and stability. In the thigh, muscles control hip and knee movements, including flexors and extensors. In the leg, the anterior, lateral, and posterior compartments contribute to dorsiflexion and toe movements, eversion, and plantarflexion. Innervation primarily comes from the sciatic nerve and its divisions, the tibial and common peroneal nerves, with the femoral nerve for the anterior thigh and the obturator nerve for the medial thigh.

Blood supply is provided mainly by the femoral artery in the thigh, continuing as the popliteal artery behind the knee, and giving rise to the anterior and posterior tibial arteries in the leg. Venous drainage involves deep and superficial systems, with deep vein thrombosis as a potential complication after injury or surgery.

Functionally, the lower extremity bears weight, enables locomotion, and absorbs impact during walking and running. Clinically, it is involved in fractures of the femur, tibia, or fibula; knee ligament injuries; ankle sprains; foot deformities; vascular or neuropathic disorders; infections; and, in severe cases, amputation.