Cruveilhier plexus: an anatomical study and a potential cause of failed treatments for occipital neuralgia and muscular and facet denervation procedures

Abstract

Object The nerves of the posterior neck are often encountered by the neurosurgeon and are sometimes the focus of denervation procedures for muscular, joint, or nervous pathologies. One collection of fibers in this region that has not been previously investigated is the Cruveilhier plexus, interneural connections between the dorsal rami of the upper cervical nerves. Methods Fifteen adult cadavers (30 sides) were subjected to dissection of the upper cervical and occipital regions with special attention given to identifying potential connections between adjacent extradural dorsal rami of the cervical nerves. When connections were identified, measurements were made and random samples were immunohistochemically stained. Results At least one communicating branch was identified on 86.7% of sides. Sampled nervous loops were composed primarily of sensory fibers, but occasional motor fibers were identified. For C-1, a communicating loop joined the medial branches of C-2 on 65.4% of sides. On 29.4% of sides, this loop pierced the obliquus capitis inferior muscle before joining C-2. On 54% of sides, a communicating loop joined the medial branches of the dorsal rami of C-2 and C-3; and on 15.4% of sides, a communicating loop joined the medial branches of the dorsal rami of C-3 and C-4. No specimen had communicating branches between the dorsal rami of cervical nerves C-5 to C-8. Articular branches arose from the deep surface of the interneural connections as they crossed the adjacent facet joint on 34.6% of sides. Loops giving rise to fibers that terminated into surrounding musculature were seen on 35% of sides. Conclusions Physical examinations that reveal unexpected results, such as altered sensory dermatome findings, may be attributed to the Cruveilhier plexus. Based on findings in the present study, surgical procedures, such as those aimed at completely denervating the upper posterior cervical musculature, facets, or nerves supplying the skin of the occiput, must also transect the Cruveilhier plexus.