Cervical zygapophysial joint pain maps.

OBJECTIVE To determine the patterns of referred pain in patients with proven cervical zygapophysial joint pain. DESIGN The pain drawings were analyzed of patients with neck pain or headache who underwent controlled, diagnostic blocks, to test whether a zygapophysial joint was the source of their pain. The distribution of pain reported by each patient who had a positive response to blocks at a particular segmental level was copied onto a grid map in order to construct a composite map of the pain patterns of that segment. Based on the prevalence of a particular joint being symptomatic and the frequency with which it referred pain to particular areas, maps were constructed to indicate the probability of a particular joint being the source of pain in a given area. RESULTS As reported by patients, the location and distribution of pain from particular cervical zygapophysial joints varies considerably; more so than in studies of normal volunteers. Nevertheless, segmental patterns could be identified. Although the pain patterns of adjacent segments overlap, those of remote segments do not. Furthermore, certain guidelines could be derived by which practitioners might distinguish pain from adjacent segments. CONCLUSION Pain maps based on areas in which patients are relieved of pain by controlled blocks provide a more representative guide to the recognition of the segmental origin of cervical zygapophysial joint pain than do maps derived from normal volunteers.