BL25 is located 1.5 cun lateral to the lower border of the spinous process of which vertebra?

• A. L3
• B. L4
• C. L5
• D. S1

Answer: (B)

Back-shu points are positioned 1.5 cun lateral to the lower border of the spinous process of a specific vertebra, aligning with the organ they govern. The Large Intestine back-shu point sits at the level of the fourth lumbar vertebra, 1.5 cun to the side of the spinous process. To locate L4 reliably, use the Tuffier’s line—the line drawn between the highest points of the iliac crests—which typically crosses the spine at L4. So BL25 is located 1.5 cun lateral to the lower border of the L4 spinous process.

If you’re thinking about the other levels, L3 would be one level higher, L5 would be one level lower, and S1 is in the sacral area, not the lumbar region where this back-shu point is found.