Anatomy, Bones

Excerpt

Bones are often considered static structures that only offer structural support (see Image. Parts of a Long Bone). However, bones have many functions, like other organ systems. Besides serving as a framework for soft tissue, bones permit locomotion, protect vital organs, facilitate breathing, play a role in electrolyte homeostasis, and are the sites of hematopoiesis. Bone remodeling continues throughout life, driven by physiologic demands.

The skeletal system can respond to increased mechanical stress by activating osteogenesis—the bone formation process. This ability is evident in how resistance training shapes the body. Resistance exercise has proven to be a viable therapeutic option for osteosarcopenia or age-related bone and muscle loss.

Bones adapt in response to both external and internal stimuli. Unlike other organs, these hard structures may break when subjected to excessive force but regenerate without fibrosis or scarring.

Human infants typically have 270 bones, fusing into 206 to 213 bones in the human adult. The variability in number arises from variations in the anatomy of some bony locations. Bones differ in size, shape, and strength, depending on function. This topic focuses on bone anatomy and function and the clinical conditions involving these structures.