The direct connections of the C2 dorsal root ganglia in the Macaca irus monkey: relevance to the chiropractic profession.

In order to assess the direct connections of the C2 Dorsal Root Ganglion, the right ganglion in each of three Macaca Irus Monkeys was injected with labelled 3H-leucine. After survival times of 24 hours and autoradiographic techniques, the slides were read using light and dark field microscopes and mapped onto enlarged cross sectional drawings. Results show labelling into the lateral cervical nucleus, the central cervical nucleus and caudal to C5 of the spinal cord. Cephalad projections were into the medullary nuclei: cuneatus, lateral cuneatus, nucleus tractus solitarius, intercalatus, and X of the vestibular system. The relevance to chiropractic therapeutics is outlined, and this data will be used in a later paper to outline the office routine for assessing vertigo/dizziness of cervical origin.