In the lumbar region, 1.5 cun lateral to the inferior border of the spinous process of the fourth lumbar vertebra (L4). At the level of the iliac crest.
🧭 How to find it (practical)
In ventral or lateral decubitus, first locate Yao Yang Guan (GV-3) at the level of the iliac crest. Locate Da Chang Chu (BL-25) 1.5 cun lateral to Yao Yang Guan (GV-3).
🔬 Anatomy
Thoracolumbar fascia, erector spinae, and quadratus lumborum muscles. Innervated by the dorsal branches of the lumbar nerves.
💉 Needling
Perpendicular or oblique insertion toward the spine, 0.8–1.2 cun.
📜 Etymology
Da Chang (大肠), Large Intestine; Shu (俞), point. Place where the Qi of the Da Chang (Large Intestine) reaches the back.
