The innervation of the cervical facet joints-an anatomical and histological approach.

Cervical facet joint pain syndrome accounts for a great amount of cervical pain worldwide. This study aims to provide updated knowledge of cervical facet joint innervation with new anatomical findings. Twenty-seven cervical facet joints and their innervating structures were dissected from five halves of three human neck specimens. Histologic staining was used to confirm that the samples were nervous tissues, and all samples were documented with photography. Histology: Thirty-six assumed facet joint branch samples were obtained and stained. Twenty-two of these were confirmed to be nervous tissue. Therefore, 61% of the samples were identified as facet joint branches. Of all samples, 28% were not nerves. Dissection: At least one medial branch was clearly identified at each dissected cervical level. At some cervical levels, more than one medial branch was found. Anatomical differences, such as a plexus-like innervation in the high cervical region, were observed. Direct facet joint branches were also discovered. These branches originate directly from the dorsal root of the spinal nerve and were independent from medial branches during their direct pathway toward the facet joint. Direct cervical facet joint branches were identified and a more diverse innervation pattern than previously described of the cervical facet joints was found.