Spinal muscle in scoliosis. Comparison of normal and scoliotic rabbits.

Spinal muscle biopsies from 7 rabbits with experimentally-produced scoliosis and from 4 normal control rabbits, were examined histologically and histochemically. One scoliotic rabbit showed selective Type 2 fibre atrophy in its muscles, but in general there was no difference between the normal and the scoliotic rabbits. The percentage area of muscle occupied by Type 1 and Type 2 fibres was determined using a computer controlled microscope. There was no asymmetry in the muscles of either the normal or the scoliotic rabbits on the two sides of the spine. These results suggest that the abnormalities and asymmetry of fibre type proportions reported in human scoliotic muscles are not a consequence of the scoliosis. Within the limits of the study, it is suggested that the abnormalities reported in the muscles of human scoliotic patients are at least an important factor in the causation of "idiopathic" scoliosis.