Abstract: Objective　To evaluate the symmetry and morphologic characteristics of the paravertebral muscle in adolescent idiopathic scoliosis (AIS) patients by ultrasound, so as to provide basis for the exercise treatment of AIS.　Methods 　A total of forty-six adolescents (23 with AIS as a patient group and 23 without AIS as a control group) were collected. The thickness of paravertebral muscle (erector spinae at T12~L5 vertebral levels, multifidus at T12~S1 vertebral levels, quadratus lumborum and transversus abdominis muscle) was measured by ultrasound in resting position (prone position of lumbar and back muscles, supine position of abdominal muscles) and standing position. The rate of muscle thickness change was calculated.　Results　At resting position and standing position, the convex side thickness of erector spinae at T12~L4 vertebral levels, the multifidus of T12~S1 vertebral levels, quadratus lumborum and transversus abdominis muscle (only the rest position) of the main bending line in AIS patients was lower than that of the concave side (P<0.05). At resting position and standing position, the change rates of spinal erector contraction thickness on convex side and concave side in AIS group was lower than that in the control group (P<0.05).　Conclusions　At resting position and standing position, compared with the control group, the paraspinal muscles of AIS patients were asymmetrical in multiple vertebral segments, and the thickness of the convex paraspinal muscles were thinner in the AIS patients. 

Key words: Adolescent; ,  , Idiopathic scoliosis; ,  , Ultrasonography; ,  , Paravertebral muscle; ,  , Thickness