Abstract: The shape and curvature of the articular surface of the superior articular process of the lumbosacral vertebrae were observed and measured on 56(30 males, 26 females) adult lumbo-sacral skeletons unearthed from Qingdao and Changchun districts. The shape of the articular surface could be divided into tunnel-type, ellipse-type and irregular-type. They might be also divided into curve-type, plane-type and mixed-type according to their curvature. The number of tunnel-curve-type and the curvature radius of the articular surface increase gradually from upper to lower level, so that the moving range of the lumbosacral spine increases successively from above downward.

Key words: Lumbar zygapophyseal joint; Curvature; Mechanics