SP-15 is located on the abdomen in the depression at the lateral border of the rectus abdominis muscle at the level of the umbilicus. Which description best matches this location?

• A. The depression at the lateral border of the rectus abdominis muscle at the level of the umbilicus
• B. The depression at the medial border of the rectus abdominis muscle at the level of the umbilicus
• C. The depression at the lateral border of the external oblique muscle above the umbilicus
• D. The depression at the lateral border of the rectus abdominis muscle below the umbilicus

Answer: (A)

The key idea is identifying SP-15 by its exact abdominal landmark: a depression at the lateral border of the rectus abdominis muscle, at the level of the umbilicus. The rectus abdominis runs vertically on each side of the midline, and its lateral edge marks the spot where this point sits, aligned horizontally with the navel. The medial border would place you near the linea alba, not at the lateral edge; the external oblique location described would be higher up and not on the rectus border at the umbilical level; and being below the umbilicus would place you too low. So the pinpointed location—lateral border of the rectus abdominis at the umbilical level—best matches SP-15.