No abstract

A method is described whereby fractures of the neural arch similar to those in spondylolysis are produced experimentally. The forces, bending moments and displacements required to initiate the fractures are given; The mechanical aspects in the aetiology of spondylolysis are explained by a simplified two-dimensional force analysis.

No abstract

No abstract

Compressive tests were carried out on cadaveric lumbar intervertebral joints, before and after the neural arch was fractured. The results show that although the neural arch can play some part in resisting the intervertebral compressive force, there is no bony contact between the downward projecting tips of the inferior articular processes and the laminae of the vertebra below.