AbstractSeven clinical measurements of joint flexibilities were made in 51 girls with untreated mild idiopathic scoliosis and 65 girls with structurally normal spines. Subject ages ranged from 10 to 16 years. Abilities to have the index finger passively extended, the wrist bent, and the elbow and the knee hyperextended, along with abilities to bend the trunk voluntarily forward and to the right and left sides, were measured. The girls with scoliosis in the mean either had the same flexibilities or were less flexible than the normal girls. The study provided no evidence that untreated mild idiopathic scoliosis occurs or progresses because of increased joint flexibilities.