[ Location ] Localized in the prone position. On the lower back, 1.5 cun lateral to the lower border of the spinous process of the fourth lumbar vertebra. ( Fig.61 )
 
[Regional Anatomy] Skin→subcutaneous tissue→the aponeurosis of thelatissimus dorsi and the superficial layer of the thoracolumbar fascia→the erector spinae. Superficial layer, the distribution of the cutaneous branches of the posterior rami of the fourth and fifth lumbar nerves, and the artery and vein along with them; deep layer, the muscular branch of the posterior rami of the fourth and fifth lumbar nerves and the branches or the subordiantial ramus of the relevant artery and vein.