The LOD is P-A, S-I and L-R with right pisiform contact. Which listing is present?

• A. L ASIN
• B. L ASEX
• C. L PIEX
• D. L IN

Answer: (B)

Understanding the test here is about translating the given line-of-drive and contact into the correct lumbar listing code. The directions P-A (posterior to anterior), S-I (superior to inferior), and L-R (left to right) describe how the thrust travels in three planes, and the right pisiform contact tells you which side and which contact point is used. In this system, a lumbar listing that matches a right-sided pisiform contact with that exact combination of thrust directions is coded as L ASEX. The other options would imply different contact locations (for example, anterior contact or a left-sided or inferior contact) or a different directional pattern, so they don’t fit the specified LOD and contact. Therefore, the listing present is L ASEX.