Limbs (anatomy)

Limbs in anatomy refer to the appendages extending from the trunk of an organism. In humans, limbs are divided into two distinct types: the upper limb and the lower limb.

Upper Limb

The upper limb or arm of a human extends from the shoulder to the hand, and it is specialized for dexterity and manipulation. It consists of four major parts: the shoulder, the arm, the forearm, and the hand. Each part contains a unique structure of bones, joints, muscles, nerves, and blood vessels that contribute to its functionality.

Lower Limb

The lower limb or leg extends from the hip to the foot. It is designed for support, balance, and locomotion. The lower limb is divided into three major parts: the thigh, the leg, and the foot. Each part has a specific structure and function that contribute to the overall performance of the limb.

Development

Limb development in the human body is a complex process that begins in the embryonic stage. It involves the formation of a limb bud, the growth of the apical ectodermal ridge (AER), and the development of the zone of polarizing activity (ZPA). These processes are regulated by various genes and growth factors.

Function

The primary functions of the limbs in humans include locomotion, manipulation of objects, and body support. The upper limbs, with their ability to grasp and manipulate, play a crucial role in tasks requiring fine motor skills. The lower limbs, on the other hand, are essential for locomotion and maintaining balance.

Disorders

There are numerous disorders that can affect the limbs, ranging from congenital conditions like limb-girdle muscular dystrophy (LGMD) and limb malformations, to acquired conditions such as limb amputation and limb paralysis.

See Also

• Musculoskeletal system
• Human skeleton
• Human musculature
• Limb regeneration