Atlanto-occipital and lateral atlanto-axial joint pain patterns

Five asymptomatic subjects underwent provocative injections of the lateral atlanto-axial and atlanto-occipital joints.

This study isolated and stimulated the lateral atlanto-axial and atlanto-occipital joints via fluoroscopically guided intra-articular injections to determine if they are potential pain generators. If they are pain generators, preliminary pain pattern maps will be constructed.

The cervical zygapophyseal joints (C2-3 to C6-7) are potential pain generators as demonstrated by referred pain induced via isolated intra-articular joint injections in normal subjects. Tentative referral patterns based on direct mechanical stimulation of the lateral atlanto-axial and atlanto-occipital joints have not been reported.

Five volunteers without histories of upper cervical pain underwent two joint injections each. In all five subjects, the left atlanto-occipital and right lateral atlanto-axial joints were stimulated via injection of contrast medium causing distension of the joint capsule.

Referred pain was produced with all ten injections. The lateral atlanto-axial injections resulted in consistent referral patterns, whereas the atlanto-occipital referral patterns varied significantly. A tentative composite diagram of the experimentally induced pain was created for each joint.

This study confirms the nociceptive ability of these cervical synovial joints. This study may assist the clinician in the differential diagnosis of head and neck pain.