SP-17 is located on the lateral chest wall in which intercostal space and distance from the midline?

• A. Fifth intercostal space, 6 cun lateral to the midline
• B. Fourth intercostal space, 6 cun lateral to the midline
• C. Sixth intercostal space, 6 cun lateral to the midline
• D. Third intercostal space, 6 cun lateral to the midline

Answer: (A)

SP-17 is located on the lateral chest wall at the level of the fifth intercostal space, about six cun away from the midline. This uses two standard reference points for point location: the vertical position by intercostal space and the horizontal distance from the body's midline measured in cun. The fifth intercostal space is the space between the 5th and 6th ribs, and moving six cun laterally places the point near the mid-axillary region. In practice, this placement aligns with the lateral chest where the spleen channel travels toward the chest, giving a consistent location across different body sizes. Because this area sits close to underlying muscles and intercostal spaces, needle depth is shallow to moderate and care is needed to avoid injuring the intercostal space.