Despite much evidence of its existence, the relation between impaired ANS function and the aetiopathogenesis of AIS has attracted surprisingly little attention. Studies have shown that the left breast of girls with right convex thoracic AIS is significantly more vascular than the right one and that the mean concave minu s convex rib length in women with thoracic IS is significantly greater than the left minu s right rib length in normal women. Moreover in growing rabbits unilateral regional sympathectomy by resection of intercostal nerves carrying sympathetic fibers results in hypervascularity of the soft tissues, increased rib growth on the side of the operation and thoracic scoliosis convex to the opposite side. The results of these and of other reports provide sufficient indication of a relation between ANS dysfunction and IS, and open new views for research on the connection between the aetiology and pathogenesis of the thoracospinal deformity.