Skeletonbones

Skeletonbones are the rigid elements that form the vertebrate skeleton. They provide a framework for the body, protect internal organs, enable movement through joints and muscles, store minerals such as calcium and phosphate, and house bone marrow for blood cell production.

Anatomically, skeletonbones consist of osseous tissue organized into cortical (compact) bone on the outer surfaces and trabecular (spongy) bone inside. The tissue is highly vascular and contains bone marrow, nerves, and blood vessels. Cellular components include osteoblasts (bone-forming), osteocytes (mature cells), and osteoclasts (bone-resorbing).

Bone strength derives from a mineralized collagen matrix, with hydroxyapatite crystals embedded in organic collagen and other proteins. This composite gives bones both rigidity and some flexibility.

Growth and development occur by endochondral ossification for most long bones and by intramembranous ossification for flat bones such as many skull bones and the clavicle.

Skeletonbones are classified by shape into long bones (e.g., femur, humerus), short bones (carpals, tarsals), flat bones (cranial bones, sternum), irregular bones (vertebrae), and sesamoid bones (patella).

Bone remodeling continually adjusts bone architecture in response to use and metabolic needs, balancing formation by osteoblasts and resorption by osteoclasts. Aging and disease can alter this balance, leading to conditions such as osteoporosis or fracture.

Beyond anatomy, the study of skeletonbones intersects physiology, development, pathology, and archaeology, informing medicine, biomechanics, and evolutionary biology.