Stellate ganglion block site under ultrasound guidance.SCM: sternocleidomastoid muscle; TH: thyroid; CA: carotid artery; IJV: internal jugular vein; VV: vertebral vein; VA: vertebral artery; LC: longus colli; SA: scalenus anterior.The yellow arrow represents the direction and depth of the needle.The yellow dotted line represents the lamina profunda fasciae colli.