Despite its potential role in this condition, the TON's relationship with the surrounding structures, particularly the facet joint at the C2-3 level, remains poorly understood.
A comprehensive anatomical study was conducted on 35 embalmed and 5 fresh-frozen human adult cadavers to investigate the relationship between the TON and the C2-3 facet joint. The TON was dissected, and its morphology described using a checklist. 3D coordinates of anatomical landmarks were registered using a Microscribe digitizer, nerve crossing angles and crossing locations were calculated.
A significant association between facet joint degeneration and the presence of a TON notch was found. Lateral crossings of the TON were significantly associated with the presence of a TON notch, and a greater separation between the nerve and the facet joint decreased the likelihood of observing a notch. The angle at which the nerve crosses the joint was also significantly associated with the location where the nerve crosses the joint and the presence of a TON notch.
This study highlights the importance of both degenerative and morphological factors in the occurrence of a third occipital nerve notch in the C2-C3 facet joint. The findings suggest that the presence of a TON notch is positively associated with the degree of joint degeneration and the proximity of the nerve to the joint, and that lateral joint crossings increase the likelihood of a TON notch.
These results may have important clinical implications for the diagnosis and treatment of occipital neuralgia and underscore the need for detailed anatomical assessments in patients with occipital headaches.
anatomy
headache
