Neuromorphometric changes in the ventral spinal roots in a scoliotic animal

The morphologic changes were investigated in the ventral and dorsal spinal nerve roots in a strain of white leghorn chickens that genetically was predisposed to have idiopathic scoliosis. In the ventral spinal roots in chickens with scoliotic curves, small myelinated fibers were increased in number and appeared in clusters. The number of small fibers did not correlate with the degree or the duration of the deformity. In 8 of the 15 chickens of the genetic scoliotic strain that did not have spinal curves, changes in the myelinated fibers, similar to those in chickens with scoliotic curves, were seen. These findings suggest that abnormalities in the myelinated fibers of the ventral spinal nerve roots may be the primary genetic lesion that, with variable penetrance, influences the development of scoliosis.