Anatomy of the lesser occipital nerve in relation to cervicogenic headache

In all papers published up to now it is stated or surmised that in cervicogenic headache, described by Sjaastad and collaborators (Cephalalgia, 3(4):240–256, 1983), the painful stimulus is carried mainly or exclusively by the greater occipital nerve. As a contribution to the study in this modality of headache, the authors made 16 dissection in eight cadavers looking for the anatomical relations of the lesser occipital nerve. The results showed that the head and face pain originating from the ventral ramus of the second cervical nerve (C2) can be explained in three different ways: (1) through anatomical regional peculiarities which make it vulnerable to mechanisms of compression and stretching; (2) through the relationship between C2 ventral ramus, the superior cervical ganglion, and the ophthalmic branch of the trigeminal nerve; (3) through clinical evidence related to painful sensibility. The authors emphasize the possible role of the lesser occipital nerve on the genesis of cervicogenic headache. It is expected that the conclusions reached will be of help to clinical studies of headache.