On the chest, in the second intercostal space, 4 cun lateral to the midline (Zǐgōng REN-19), on the mamillary line, which point corresponds to this location?

• A. ST 15
• B. ST 12
• C. ST 15
• D. ST 16

Answer: (A)

The chest points along the Stomach channel are defined by exact intercostal space and lateral distance from the midline. The location described—second intercostal space, 4 cun lateral to the midline, on the mamillary line—maps to ST-15. That makes ST-15 the correct match for this spot. The other points lie in different chest locations and do not align with this specific position, so they don’t fit the described site.