[Location] Localized in the erect sitting position or prone position. On the back, 1.5 cun lateral to the lower border of the spinous process of the third thoracic vertebra. (Fig.61)
 
[Regional Anatomy] Skin→Subcutaneous tissue→the trapezius→the rhomboideus→the superior serratus posterior→the erector spinal muscle. Superficial layer, the distribution of the medial cutaneous branches of the posterior rami of the third and fourth thoracic nerves, and the medial cutaneous branches of the dorsal branches of the posterior intercostals artery and vein along with them; deep layer, the muscular branch of the posterior rami of the third and fourth thoracic nerves and the branches or the subordiantial ramus of the dorsal branches of the relevant posterior intercostals artery and vein.