Third Occipital Nerve Block

Indications and Clinical Considerations

Third occipital nerve block is useful in diagnosing and treating third occipital nerve headache. This technique is also useful as a prognostic indicator of the potential efficacy of destruction of the third occipital nerve with radiofrequency lesioning or other means. Third occipital headache is thought to find its nidus from the C2-C3 facet joints and is commonly seen in patients who have suffered cervical spine trauma following whiplash injuries. Patients suffering from third occipital headache complain of both posterior neck and occipital headache pain with demonstrable tenderness of the affected C2-C3 facet joints.

Clinically Relevant Anatomy

The third occipital nerve arises from superior branch fibers of the third cervical nerve at the level of the trapezius muscle ( Fig. 24.1 ). The third occipital nerve courses dorsomedially around the superior articular process of the C3 vertebra ( Fig. 24.2 ). Fibers from the third occipital nerve provide the primary innervation of the C2-C3 facet joints with some contribution from the C3 medial branch and small communicating fibers from the second cervical nerve. Fibers of the third occipital nerve then course superiorly to provide sensory innervation to the ipsilateral suboccipital region. When the third occipital nerve is successfully blocked with local anesthetic, the patient will experience numbness in a small area behind the ipsilateral ear ( Fig. 24.3 ).