Lower

Lower limb

Latin	membrum inferius
Nerve	Sciatic nerve, femoral nerve
System	Musculoskeletal system

The lower limb or lower extremity refers to the part of the body that extends from the hip to the toes. It includes the thigh, knee, calf, ankle, and foot. The lower limbs are essential for various functions such as standing, walking, running, and jumping. They are structurally designed to support the weight of the body and enable locomotion.

Structure

The lower limb consists of several key components:

Bones

The main bones of the lower limb include:

• Femur - the thigh bone, which is the longest and strongest bone in the body.
• Patella - also known as the kneecap.
• Tibia and Fibula - the two bones of the lower leg.
• Tarsals, Metatarsals, and Phalanges - the bones forming the foot.

Joints

Important joints in the lower limb include:

• Hip joint - a ball and socket joint between the femur and the pelvis.
• Knee joint - primarily a hinge joint between the femur, tibia, and patella.
• Ankle joint - a hinge joint between the tibia, fibula, and the talus bone of the foot.

Muscles

The lower limb contains numerous muscles which are grouped into compartments:

• Anterior thigh muscles, such as the quadriceps femoris, which extend the knee.
• Posterior thigh muscles, including the hamstrings, which flex the knee and extend the hip.
• Calf muscles, such as the gastrocnemius and soleus, which are involved in plantar flexing the foot.

Nerves

Major nerves of the lower limb include:

• Sciatic nerve - the largest nerve in the body, responsible for motor and sensory functions of the thigh, lower leg, and foot.
• Femoral nerve - innervates the anterior thigh muscles.

Vascular supply

The vascular supply to the lower limb includes:

• Femoral artery and popliteal artery - supplying blood to the lower limb.
• Femoral vein and popliteal vein - draining blood from the lower limb.

Function

The lower limbs play a crucial role in locomotion, allowing humans to walk, run, and jump. They also help maintain balance and posture.

Clinical significance

Common disorders affecting the lower limb include:

• Fractures of the femur, tibia, or fibula.
• Arthritis, particularly of the hip and knee joints.
• Peripheral artery disease, affecting the blood flow to the limbs.
• Diabetic neuropathy, which can affect the nerves of the lower limb in people with diabetes.

See also

• Upper limb
• Human skeleton
• Musculoskeletal system