LKnative - Greater occipital nerve block 
Greater occipital nerve (yellow shadow), obliquus capitis muscle (white asterisk), lamina of vertebra C2 (red asterisk).
6 – Sonoanatomy of the greater occipital nerve
The greater occipital nerve is visualized on top of the obliquus capitis inferior muscle.
The vertebral artery should be identified with color Doppler.