Which point is located on the upper arm where the line drawn between Tianjing SJ-10 and Jianliao SJ-14 meets the posterior border of the deltoid muscle, approximately two thirds of the distance between the two points?

Which point is located on the upper arm where the line drawn between Tianjing SJ-10 and Jianliao SJ-14 meets the posterior border of the deltoid muscle, approximately two thirds of the distance between the two points?

• A. SJ 13
• B. SJ 14
• C. SJ 15
• D. SJ 16

Answer: (A)

The line from Tianjing (SJ-10) to Jianliao (SJ-14) follows the pathway of the San Jiao channel up the posterior/lateral aspect of the upper arm toward the shoulder. The posterior border of the deltoid is a consistent anatomical landmark along this track. Where that line intersects the posterior border of the deltoid, about two-thirds of the way from SJ-10 toward SJ-14, sits Sanjiao 13. This location pins the point on the upper arm precisely along the deltoid’s rear edge, matching the described description.

The line from Tianjing (SJ-10) to Jianliao (SJ-14) follows the pathway of the San Jiao channel up the posterior/lateral aspect of the upper arm toward the shoulder. The posterior border of the deltoid is a consistent anatomical landmark along this track. Where that line intersects the posterior border of the deltoid, about two-thirds of the way from SJ-10 toward SJ-14, sits Sanjiao 13. This location pins the point on the upper arm precisely along the deltoid’s rear edge, matching the described description.