[Location] Localized in the prone position. On the lower back. 3 cun lateral to the lower border of the spinous process of the first lumbar vertebra. ( Fig.65 )
 
[Regional Anatomy] Skin→subcutaneous tissue→the aponeurosis of the latissimus dorsi→the erector spinae→the quadratus lumborum. Superficial layer, the distribution of the cutaneous branches of the posterior rami of the first and second lumbar nerves, and the artery and vein along with them; deep layer, the muscular branch of the posterior rami of the first and second lumbar nerves and the branches or the subordiantial ramus of the dorsal branches of the relevant lumbar artery and vein.