Idiopathic scoliosis and asymmetry of form and function.

This report investigates dimensions of hand and foot preference in 159 girls with idiopathic scoliosis diagnosed after the age of 8 years, 1,522 girls with clinically straight spines, and 132 with minor truncal asymmetry. It was found that, although there was no significant difference in hand or foot preference for individual items between scoliotic groups and controls, there was a statistically significant tendency for children with any degree of asymmetry to show uniform lateralization in the sense of consistency of side preference. Another, smaller group showed a tendency for scoliosis to be associated with clearly visible facial asymmetry, which itself correlated with handedness. It was concluded that theories of scoliosis need to include the frequently ignored minor observations, such as the well-known fact of lateralization of the curve, if they are to describe the condition completely. Because the asymmetry of cerebral lateralization is known to be genetically determined and because it is thought to result in other skeletal asymmetries, such as skull and limb inequality, it seemed reasonable to investigate the primary cause of that gross asymmetry, idiopathic scoliosis.