Abstract: Objective To study the relationship between activity of thorax and each spinal intervertebral angle in patients with ankylosing spondylitis. Methods Each spinal intervertebral angle of 41 patients with ankylosing spondylitis were measured by Spinalmouse in different postures. And the activity of thorax was measured. Correlation between activity of thorax and shape of spinal were analyzed. Results The activity of thorax positively correlated with the entire lumbar spinal column in flexion (P<0.01), as well as the intervertebral angle of L1/2, L2/3 and L4/5 in flexion (P<0.05), but negatively correlated with the intervertebral angle of L1/2 and L2/3, curvature of the entire lumbar spinal column in upright and the intervertebral angle of L1/2, L3/4, curvature of the entire lumbar spinal column in extension. Conclusion There was a significant relation between activity of thorax and lumbar vertebra motor ability.

Key words: ankylosing spondylitis, activity of thorax, spine, motor ability