The effect of four types of support on the segmental mobility of the lumbosacral spine.

With the aid of flexion-extension lateral radiographs, we investigated the effect of the canvas corset, the Raney and Baycast jackets, and the Baycast spica on the segmental sagittal mobility of the lumbosacral spine in separate groups of five volunteers each. The canvas corset reduced the mean angular movements at each level to two-thirds of normal. The Raney and Baycast jackets reduced the mean angular movements in the middle of the lumbar spine to approximately one-third of normal. The Baycast spica was the most effective in restricting angular movements below the third lumbar vertebra, and especially at the fourth lumbar-fifth lumbar level and the lumbosacral level.