List of bones in the human body

List of bones in the human body

System	Skeletal system

The human body is composed of over 200 bones at birth. This number decreases to around 206 by adulthood after some bones have fused together. The bone mass in the skeleton reaches maximum density around age 21. The human bones provide support for the body, protect organs, anchor muscles, and store calcium. Bones are classified by their shape: long, short, flat, and irregular.

Overview

The skeletal system is divided into two parts: the axial skeleton and the appendicular skeleton. The axial skeleton includes the bones of the skull, vertebral column, and rib cage. The appendicular skeleton includes the bones of the arms, legs, pelvis, and shoulder area.

Axial Skeleton

The axial skeleton forms the central axis of the human body and includes 80 bones in the following regions:

• Skull - Comprising 22 bones, including the mandible (1) and the maxilla (2).
• Vertebral column - Consisting of 33 vertebrae in the adult body, divided into the cervical (7), thoracic (12), lumbar (5), sacral (5 fused), and coccygeal (4 fused).
• Thoracic cage - Comprising the sternum (1) and ribs (24).

Appendicular Skeleton

The appendicular skeleton consists of 126 bones in the limbs and girdles. It is divided as follows:

• Pectoral girdles (shoulder girdles) - Each consisting of a clavicle (1) and a scapula (1).
• Upper limbs - Including the humerus (1), radius (1), ulna (1), carpal bones (8), metacarpal bones (5), and phalanges (14) in each arm.
• Pelvic girdle - Formed by the hip bones (2), which are each composed of the fused ilium, ischium, and pubis.
• Lower limbs - Including the femur (1), patella (1), tibia (1), fibula (1), tarsal bones (7), metatarsal bones (5), and phalanges (14) in each leg.

Function

Bones serve multiple roles in the body — most importantly, they provide structure, protect organs, anchor muscles, and store calcium. While all bones within the body are connected to muscles and joints, their sizes and shapes are indicative of their functions. Long bones, such as the femur, provide leverage and mobility. Flat bones, such as the ribs, provide protection for vital organs. Short bones, such as the carpals, are adapted for stability and support, whereas irregular bones, such as the vertebrae, protect the spinal cord and have other specialized functions.

Bone Health

Maintaining bone health is crucial for the skeletal system's function. Factors that influence bone health include nutrition, physical activity, and other lifestyle choices. Calcium and vitamin D are essential for maintaining strong bones and preventing osteoporosis, a condition that weakens bones, making them fragile and more likely to break.

See also

• Bone marrow
• Bone remodeling
• Osteology
• Skeletal system

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