The anterior and the posterior longitudinal ligaments of the lower cervical spine.

The anterior and the posterior longitudinal ligaments (ALL and PLL) of the cervical spine were examined. The ALL and the deep layer of the PLL are continuous, and surround the vertebral body. The superficisl layer of the PLL surrounds the dura mater, nerve roots and the vertebral artery, suggesting that this membrane may serve as a protective membrane for the soft tissues inside the vertebral canal rather than as a conventional ligament.