The anterior drawer and Lachman tests assess the integrity of which knee structure?

• A. Lateral collateral
• B. Anterior cruciate ligament
• C. Posterior cruciate ligament
• D. Medial collateral

Answer: (B)

These tests target the ACL because they measure how much the tibia can move forward relative to the femur, which is exactly what the ACL normally restrains. In the anterior drawer test, the knee is flexed to about 90 degrees and the tibia is pulled forward; increased anterior translation and a reduced or absent end point indicate ACL deficiency. The Lachman test, performed with the knee flexed to roughly 20–30 degrees, is more sensitive because it places the ACL in a position where it provides the most restraint while minimizing hamstring resistance, so a noticeable forward movement of the tibia with a soft or absent end point strongly suggests an ACL tear.

The others involve different structures. The collateral ligaments (lateral and medial) are assessed with varus/valgus stress tests, not these anterior-focused maneuvers. The posterior cruciate ligament is assessed with a posterior drawer test, which looks for excessive backward movement of the tibia.