The cervical locking mechanism. Its contribution to the cervical spine stability and to the vertebral artery and spinal cord safety. An anatomical study.

Investigations were conducted with macerated cervical vertebrae and human cadavers. During extension, lateral flexion, and rotation of the neck, the cervical transverse process engages to the top of the upper articular process of the subjacent vertebra, thus embodying the locking mechanism which plays an important role in the stabilization of the cervical spine and the protection of the integrity of vertebral arteries, spinal cord, and nerve roots. A deficiency of this locking mechanism may cause a vertebrobasilar insufficiency or a cervical myelopathy.