Dìng Chuān (M-BW-1) is located at the back of the neck near which vertebral feature?

• A. 0.5 to 1 cun lateral to the depression below the spinous process of the seventh cervical vertebra
• B. 1.5 cun lateral to the spinous process of T5
• C. 3 cun lateral to the midline at Ren-3 level
• D. Behind the ear, midway between GB-20 and SJ-17

Answer: (A)

Focus on the anchor point at the back of the neck: the spinous process of the seventh cervical vertebra, the vertebra prominens. Just below that bump is a small depression, and Dìng Chuān sits 0.5 to 1 cun to the side of that depression. This places the point in the upper, posterior neck region rather than on the midline lower down or behind the ear.

The other described locations would place the point in different areas: down near T5, at Ren-3 level, or behind the ear between GB-20 and SJ-17, which do not correspond to the back-of-neck location defined for Dìng Chuān.