For sacral P-L/P-R, which description best matches its line of drive?

• A. P-A only
• B. P-A, S-I
• C. P-A, M-L through joint plane
• D. P-A with torque

Answer: (C)

The line of drive for sacral P-L/P-R follows the orientation of the sacroiliac joint plane, which is oblique relative to the standard planes. To address a sacral torsion pattern on these sides, you want a thrust that moves from posterior toward anterior while also having a medial-to-lateral component that runs through the joint plane. This engages the sacral oblique axis and directs force along the joint surface, effectively correcting the torsion. Purely a posterior-to-anterior push or a thrust with only torque or a simple anterior-to-posterior direction would not align with the joint plane and would be less effective at restoring the sacrum’s alignment. So the best description is a posterior-to-anterior line with a medial-to-lateral component through the joint plane.