The sinuvertebral nerves at the craniovertebral junction: a microdissection study.

Bogduk et al. (1988, Spine 13:2-8) noted that the joints and ligaments at the cervico-occipital region are susceptible to whiplash injury. The upper three cervical sinuvertebral nerves (SVNs) at the craniovertebral junction (CVJ) are thought to be responsible for mediating pain from the ligaments, dura mater, and soft tissues of the posterior cranial fossa and upper cervical column. The purpose of this study was to describe in detail the origin and course of the SVNs at C0-C1, C1-C2, and C2-C3 intervertebral levels and their anterior intraspinal distribution. A sample comprising 10 adult, 12 fetal (crown rump length = 155-250 mm), and three stillborn neonatal (n = 50 sides) embalmed cadaveric cervical spines was microdissected (Carl Zeiss, Jena, Germany, 8-40× magnification). A laminectomy of the cervical spine with an occipital craniectomy (seven adult and all fetal specimens) or a horizontal section of the intervertebral levels was performed (three adult specimens) to expose the craniocervical canal. In both adult and fetal specimens, all three cervical SVNs arose from two roots, a somatic root (from the spinal nerve or ventral ramus or both) and a sympathetic root (from the vertebral artery plexus or superior cervical ganglion). The C1 and C2 SVNs were variable in number. The C2 and C3 SVN innervated most of the structures at the CVJ as well as the basiocciput region. The C1 SVN supplied a very small part of the atlanto-occipital joint area. The intraspinal courses of all three SVNs consisted of ascending and descending branches closely adherent to the arteries of the CVJ. They supplied the dura mater, the ligaments, adjacent joints, and soft tissues by tiny branches from the main branches. The detailed origins and course are described.