The intertransversarii muscle contributes most to which movement?

• A. Extension of the spine
• B. Rotation of the spine
• C. Flexion of the spine
• D. Lateral flexion and stabilization of the spine

Answer: (D)

Intertransversarii are small muscles that run between adjacent transverse processes along the spine, and their main job is to control side-to-side bending and stabilize the spinal segment. When you bend to one side, the fibers on that side pull the vertebrae closer together, producing lateral flexion, while their position also helps maintain joint stability during movement. They’re not the primary movers for spine extension, flexion, or rotation—those functions come from other muscles like the back extensors for extension, abdominal/psoas muscles for flexion, and the rotatores/multifidus for rotation. So their strongest contribution is lateral flexion and stabilization of the spine.