Referred pain distribution of the cervical zygapophyseal joints and cervical dorsal rami.

The purpose of this study was to determine the distribution of referred pain from the cervical zygapophyseal joints (C0/1 to C7/Th1) and the cervical dorsal rami (C3 to C7). The subjects were 61 patients who had occipital, neck, and shoulder pain of suspected zygapophyseal origin in whom pain was reproduced by injection of contrast medium into the joints or by electrical stimulation of the dorsal rami. Under fluoroscopic control, the zygapophyseal joints from C0/1 to C7/Th1 were stimulated by the injection of contrast medium and while electrical stimulation of the cervical zygapophyseal dorsal rami at segments C3 to C7 was performed during facet denervation. If injection or electrical stimulation reproduced the patient's usual pain, the distribution of referred pain was determined and the sites of referred pain were divided into 10 areas. A total of 181 joints and 62 segments were studied. Each joint and dorsal ramus produced referred pain with a characteristic distribution. The main distribution of referred pain was as follows. Pain in the occipital region was referred from C2/3 and C3, while pain in the upper posterolateral cervical region was referred from C0/1, C1/2, and C2/3. Pain in the upper posterior cervical region was referred from C2/3, C3/4, and C3, that in the middle posterior cervical region from C3/4, C4/5, and C4, and that in the lower posterior cervical region from C4/5, C5/6, C4, and C5. In addition, pain in the suprascapular region was referred from C4/5, C5/6, and C4, that in the superior angle of the scapula from C6/7, C6, and C7, and that in the mid-scapular region from C7/Th1 and C7.