Appendicular skeleton

Appendicular Skeleton

The appendicular skeleton is a component of the human skeleton that includes the limbs, or appendages, of the body. It is one of the two main divisions of the human skeleton, the other being the axial skeleton. The appendicular skeleton consists of 126 bones in adults, which are organized into the upper limbs (arms and hands), the lower limbs (legs and feet), and the pelvic girdle and pectoral girdle.

Structure

The appendicular skeleton is divided into six major regions:

1. Upper limbs: Each upper limb includes a humerus, radius, ulna, carpals (wrist bones), metacarpals (hand bones), and phalanges (finger bones).

2. Lower limbs: Each lower limb includes a femur, patella, tibia, fibula, tarsals (ankle bones), metatarsals (foot bones), and phalanges (toe bones).

3. Pelvic girdle: The pelvic girdle, or hip girdle, consists of two hip bones, each of which is formed by the fusion of three bones: the ilium, ischium, and pubis.

4. Pectoral girdle: The pectoral girdle, or shoulder girdle, consists of two clavicles (collarbones) and two scapulae (shoulder blades).

Function

The primary function of the appendicular skeleton is to provide support and flexibility for movement. The bones of the appendicular skeleton serve as attachment points for the skeletal muscles, which allow for a wide range of motion. The appendicular skeleton also protects some of the body's major organs, such as the heart and lungs, which are shielded by the pectoral girdle.

Clinical significance

Diseases and disorders of the appendicular skeleton can significantly impact a person's mobility and quality of life. These include fractures, arthritis, osteoporosis, and cancer. Treatment options for these conditions vary, but may include surgery, physical therapy, and medication.

See also

• Bone
• Musculoskeletal system
• Human skeleton