The normal and degenerate lumbar intervertebral disc. The figure shows a normal intervertebral disc on the left. The annulus lamellae surrounding the softer nucleus pulposus are clearly visible. In the highly degenerate disc on the right, the nucleus is desiccated and the annulus is disorganized.
Urban and Roberts Arthritis Res Ther 2003 5:120 doi:10.1186/ar629