Which muscles comprise the Posterior Oblique System?

• A. Latissimus Dorsi
• B. Latissimus Dorsi; Contralateral Gluteus Maximus
• C. Latissimus Dorsi; Gluteus Maximus
• D. Erector Spinae

Answer: (B)

The Posterior Oblique System is a diagonal linkage that stabilizes the spine and pelvis by tying the upper body to the opposite side of the pelvis. It relies on the latissimus dorsi on one side working together with the contralateral gluteus maximus, connected through the thoracolumbar fascia. This cross-body pairing allows force to be transferred efficiently from the arm through the torso to the opposite hip and leg, which is crucial for rotation, walking, and load-bearing movements. The other options don’t form this diagonal, cross-body connection: pairing the latissimus dorsi with the same-side gluteus maximus lacks the opposite-side linkage, and including the erector spinae alone doesn’t complete the posterior oblique system. Therefore, the correct pairing is latissimus dorsi with the contralateral gluteus maximus.