DOI link for ◾ Orthopedics
◾ Orthopedics book
Bones function to provide structural support for the body, allow movement by providing levers for muscles, maintain mineral homeostasis, and serve as a hematopoietic organ. e long bones of the extremities are composed of the tubular sha (diaphysis), the rounded epiphysis at both ends, and the metaphysis between the diaphysis and epiphysis, just below the growth plate. Bone tissue is classied as cortical and cancellous bone, and the relative proportion of these two types of bony tissue in any bone depends on the specic bone and its skeletal location. Cortical bone is solid and dense, usually surrounds the marrow space, and constitutes the diaphysis and surface of long bones, as well as the surface of vertebrae and other short or irregular bones. Cancellous or trabecular bone is less compact than cortical bone, consists of a meshwork of trabecular plates and rods interspersed within the marrow space of the metaphysis and epiphysis, and is highly vascular. Cells responsible for bone remodeling, the osteoblasts and osteoclasts, are situated both in the endosteum lining the bone marrow space and the periosteum covering the outer cortical bone surface, and these sites of metabolic activity can be indirectly assessed through blood chemistry and radionuclide imaging studies. Bone pathologies frequently seen in orthopedics include traumatic or pathologic fractures and dislocation, infection, avascular necrosis, tumors, osteoporosis, metabolic disorders, and congenital bone disease (Clarke 2008, Gardner 1963).