Anatomic relation between the nuchal ligament (ligamentum nuchae) and the spinal dura mater in the craniocervical region

There are inconsistencies between the descriptions of the physical connections between the spinal cervical dura and the surrounding tissues. This study was undertaken to clarify the relationship between the spinal dura, the nuchal ligament and the suboccipital muscles. Dissections were performed on embalmed cadavers: in nine the relevant structures were removed en bloc, whereas in one a sagittal section was prepared. In all specimens it was possible to demonstrate continuity in the midline between the nuchal ligament and the posterior spinal dura at the atlanto-occipital and atlanto-axial intervals. No such attachments were found caudal to the arch of the axis. In addition, there was a connective tissue bridge between the deep aspect of the rectus capitis posterior minor muscle to the transverse fibers of the posterior atlanto-occipital membrane that extended laterally to blend with the perivascular tissue of the vertebral arteries. The present study is, we believe, the first to describe continuity between the nuchal ligament and the dura at the atlanto-occipital interspace, and confirms previous descriptions of similar connections at the atlanto-axial level. Knowledge of the exact attachments of the dura may contribute to understanding the biomechanics of the cervical spine and of the possible etiology of some types of cervicogenic headaches.