Definition:
The 206 bones of the skeletal system perform the mechanical functions of support, protection, and body movement and the metabolic functions of hemopoiesis and mineral storage.

Functions: 1) Support--The skeleton forms a rigid framework to which are attached the softer tissues and organs of the body. 2) Protection--The skull and vertebral column enclose the central nervous system; the rib cage protects the heart, lungs, great vessels, liver, and spleen; and the pelvic cavity supports and protects the pelvic viscera. Even the sites where most of the blood cells are produced is protected within the central, hollow portion of the bone. 3) Body movement--Bones serve as anchoring attachments for most skeletal muscles. In this capacity, the bones act as levers with the joints functioning as pivots when muscles contract to cause body movement. 4) Hemopoiesis--The red bone marrow of an adult produces white blood cells, red blood cells, and platelets. 5) Mineral storage--The inorganic matrix of bone is composed primarily of the minerals calcium and phosphorus. These minerals give bone its rigidity and account for approximately two-thirds of the weight of bone. About 95% of the calcium and 90% of the phosphorus within the body are deposited in the bones and teeth.

Clinical Information
Achondroplasia. A genetic defect resulting in the retarded formation of cartilaginous bone during fetal development.
Bone fracture. The cracking or breaking of a bone; they can be pathological or traumatic.
Orthopedics. A branch of medicine concerned with the diagnosis and treatment of trauma, diseases, and abnormalities involving the skeletal and muscular systems.
Osteomyelitis. An inflammation of bone marrow caused by bacteria or fungi.
Osteopathology. The study of bone diseases.
Osteosarcoma. A malignant tumor of bone tissue.
Rickets. A calcium and vitamin D deficiency of early childhood which leads to demineralization of bones and deformities.