Occipital Nerve Block
Occipital nerve block is useful diagnostically and therapeutically in patients with occipital headaches and neuralgias.
The greater occipital nerve is derived from the dor-sal primary rami of the C2 and C3 spinal nerves, whereas the lesser occipital nerve arises from the ventral rami of the same roots.
The greater occipital nerve is blocked approximately 3 cm lateral to the occipital prominence at the level of the superior nuchal line ( Figure 47–10); the nerve is just medial to the occipital artery, which is often pal-pable. The lesser occipital nerve is blocked 2–3 cm more laterally along the nuchal ridge. Ultrasoundguidance may be employed to help identify the nerves and minimize the risk of inadvertent intra-venous or intraarterial injection. For patients who have responded well but temporarily to occipital
nerve blocks, implantation of an occipital nerve stimulator may provide prolonged relief.
Rarely, intravascular injections may occur.