Scoliosis and trunk muscles.

This study examines the role of muscular deficiencies in the origin and development of paralytic scoliosis. We studied spine films of 108 scoliotic curves of poliomyelitic children and results of muscle tests made during the growth phase. We investigated the relationship between spinal and abdominal muscle test values, determined 2 years after the child had experienced the acute phase of anterior polioimyelitis, and the convexity, evolution rate, effects of gravity, and reducibility of the scoliotic deformity. Although paralysis certainly is responsible for triggering scoliosis, it plays no role in determining convexity for thoracic and lumbar patterns, and has little bearing on thoracolumbar curves. It is not at all correlated with the evolution rate, reducibility, or degree of collapse with gravity. The general laws governing the evolution of scoliosis, whatever its origin, are outlined, and several possible pathogenic factors are suggested.