Limbs

Limbs

Latin	Membrum
Nerve	Various
System	Musculoskeletal system

Limbs are appendages of the body that are used primarily for movement and manipulation of the environment. In vertebrates, limbs take various forms, such as legs, arms, or wings, and are crucial for locomotion, feeding, and other activities.

Structure

Limbs are connected to the main body through a joint, allowing for a range of movements. The structure of limbs generally includes bones, joints, muscles, tendons, and ligaments. The skeletal structure provides the necessary support, while the muscles power the movement by contracting and relaxing. Nerves supply the muscles and skin of the limbs, enabling control and sensation.

Types of Limbs

• Upper Limbs: Typically referred to as arms in humans, these are used for manipulation, grasping, and sensory reception.
• Lower Limbs: Commonly known as legs, these are primarily used for support, balance, and locomotion.
• Wings: Found in birds and some other animals, wings are specialized limbs used for flying.

Function

The primary function of limbs is to provide mobility and enable interaction with the environment. This includes walking, running, jumping, and in the case of arms, manipulating objects. Limbs also play a crucial role in non-verbal communication and body language.

Evolution

The evolution of limbs is a significant aspect of the evolution of vertebrates. Limbs first appeared in the form of fins in early aquatic vertebrates. Over millions of years, these evolved into the limbs seen in amphibians, reptiles, birds, and mammals. This evolutionary process involved changes in the skeletal structure, muscle arrangement, and overall function, adapting each type of limb to specific environmental challenges.

Development

Limbs develop in the embryo from limb buds, which grow and differentiate into various components under the influence of genetic and molecular factors. This development is highly regulated to ensure proper formation and symmetry.

Clinical Significance

Various conditions can affect the limbs, including trauma, infections, congenital disorders, and diseases that impair their function. Treatment depends on the specific condition but may include medical therapy, surgical intervention, and physical rehabilitation.

See Also

• Musculoskeletal system
• Human anatomy
• Evolution of vertebrates