Some Mechanical Tests on the Lumbosacral Spine with Particular Reference to the Intervertebral Discs

Abstract

The effect of stress on the lumbar intervertebral discs was tested by actual compression, tensile strength, combined axial-load bending tests and fatigue tests. Under axial compressive stress, failure of the disc complex took place in the cartilaginous plate. Failure of the annulus fibrosus occurred only as a result of extremely rapid cyclic bending combined with mild axial compression. The annulus had a weight-bearing function. Under axial compression the intervertebral discs lost volume before there was failure and tearing of the annulus fibrosus.