outer (exterior) mound

When the back of the foot is forcefully flexed, 1.5 cun outside [lateral] of the depression at the center of the line drawn by the gastrocnemius muscles (or Chéng Shān point 承山, BL-57). If the line of the gastrocnemius muscle is not obvious, one can deviate 1.5 cun outside [lateral] from the center of a line uniting the points Wěi Zhōng 委中, BL-40 and Kūn Lún 昆侖, BL-60 (Chéng Shān 承山, BL-57).