Deep perpendicular insertion carries a risk of puncturing the kidney.
📍 Location (classical)
In the lumbar region, 1.5 cun lateral to the inferior border of the spinous process of the first lumbar vertebra (L1).
🧭 How to find it (practical)
In ventral or lateral decubitus, locate the point below the spinous process of the first lumbar vertebra, 1.5 cun lateral to the posterior midline, lateral to Xuan Shu (GV-5).
🔬 Anatomy
Thoracolumbar fascia, latissimus dorsi, and erector spinae muscles. Innervated by the dorsal branches of the 10th–12th thoracic nerves and the first lumbar nerve.
💉 Needling
Perpendicular or oblique insertion toward the spine, 0.5–1.0 cun.
📜 Etymology
San (三), three; Jiao (焦), cavity, part; Shu (俞), point. Place where the Qi of the San Jiao reaches the back.
