Most physicians' first exposure to the musculoskeletal system is in the anatomy laboratory. Bones, muscles, origins and insertions, and nerve and blood supply are laboriously memorized and quickly forgotten. The biology of muscle function learned in physiology also becomes indistinct. The musculoskeletal system is a biological unit whose function is mechanical. Early application of the concept of the mechanical function of a biologic unit was perhaps best exemplified in the treatment of the sequelae of poliomyelitis. An unopposed muscle force produced functional or static deformity, and treatment often consisted of balancing these forces.
The study of the biomechanics of the musculoskeletal system received great impetus immediately after World War II in attempting to solve the problems of prosthetic substitution from amputated extremities. From these beginnings the interest and application of biomechanical studies to other clinical problems has rapidly expanded. The increased interest in biomechanics has been evidenced by the institution