The role of the vertebral laminae in the stability of the cervical spine.

The aim of this study was to determine the contribution of the vertebral laminae to the stability of the cervical spine since laminectomy may result in deformity of the neck. In 40 dry adult male cervical columns the weight-bearing areas of the inferior surfaces of the bodies and articular facets from C2 to C7 were measured and the means and S.D.S. calculated. In all columns the lamina index (height x thickness) of right and left halves of each lamina was calculated and summed at each cervical level. Means and S.D.S. were calculated for the series. The trabecular patterns in the laminae were studied in 6 of the columns. Results show that the laminae of C2 and C7 are heavily loaded, whilst the intervening ones are not. Thus laminectomy at C2 and C7 would tend to lead to instability, but between C3 and C6 this would be less likely. Significant segmental variation in weight transmission was not found for the facet joints.