Limb

Limb

A limb or extremity is a jointed, or prehensile (as octopus arms or new world monkey tails), appendage of the human or other animal body. In the human body, arms and legs are commonly referred to as limbs, while the term "extremity" is used to refer to an arm or a leg.

Anatomy

Most animals use limbs for locomotion, such as walking, running, or climbing. Some animals can use their front limbs (or upper limbs in humans) to carry and manipulate objects. Some animals can also use hind limbs for manipulation.

Human limbs

In humans and other primates, the upper limbs are commonly called arms and the lower limbs legs.

Arms

The human arm is composed of three long bones, joined together by hinges and ball-and-socket joints. The humerus is the uppermost and largest bone of the arm, extending from the shoulder to the elbow.

Legs

The human leg is the entire lower limb, including the foot. In terms of anatomy, the leg is just the part of the lower limb extending from the knee to the ankle.

Evolution

The evolution of limbs is a fascinating area of study in the field of evolutionary biology. The first tetrapods evolved from the lobe-finned fishes in the Devonian.

See also

• Arm
• Leg
• Evolution of tetrapods
• Limb development