C2 dorsal root ganglion: the central hub for cervicogenic headache

PURPOSE OF REVIEW: The purpose of this review is to provide an update on the mechanisms of cervicogenic headache and the role of the C2 dorsal root ganglion (DRG) as a central hub for cervicogenic headache. RECENT FINDINGS: The suboccipital muscles have been implicated in the pathogenesis of cervicogenic headaches due to their connections with the dura mater. The myodural bridge (MDB) connects the suboccipital musculature to the spinal dura mater as it passed through the posterior atlanto-occipital and the atlanto-axial interspaces. The C1-C3 spinal nerves, the suboccipital muscles, and their MDBs are now well-recognized sources of cervicogenic headache. SUMMARY: We propose the C2 DRG as the central hub in cervicogenic headache. Because the C2 DRG receives afferent input from both C1 and C2, its blockade may disrupt sensory transmission from C1 to C3, the primary contributors to cervicogenic headache. Blocking the C2 DRG and the MDBs deep to the obliquus capitis inferior muscle can be highly effective in both the diagnosis and management of cervicogenic headache.