SKELETAL SYSTEM - BIOMECHANICAL CONCEPTS AND RELATIONSHIPS TO NORMAL AND ABNORMAL CONDITIONS

The human skeleton is a remarkable organ that is uniquely designed to provide structural support and to house the body's hematopoietic syste m and mineral resevoirs. Seven concepts that will assist the clinician in understanding skeletal function are (1) material properties of bon e, (2) stress and strain, (3) bending moments and torsional loads, (4) area moments of inertia, (5) fatigue and catastrophic failure, (6) Wo lff's law, and (7) stress risers and open section effect, For example, as the modulus of a bone, a measure of stiffness decreases as in Padg et's disease or fibrous displasia and the same levels of stress will c ause greater deformations. The sum of these principles also explains t he torus fracture (ductility), fracture of the olecranon by contractin g tricep muscle (tensile loading), osteoporotic compression fracture o f the spine, and the other biomechanical lesions that are encountered, Understanding these basic biomechanical principles can help physician s comprehend neoplastic processes and fractures that are the metabolic responses of the skeleton to stress and that appear on the radionucli de bone scan. Copyright (C) 1997 by W.B. Saunders Company.