Which region is the most mobile portion of the spine?

• A. Cervical spine
• B. Thoracic spine
• C. Lumbar spine
• D. Sacral spine

Answer: (A)

Mobility across the spine varies by region because anatomy drives how much movement each part can allow. The neck section is designed for head movement, with the atlas and axis forming a pivot that enables substantial rotation, and the lower cervical vertebrae contributing flexion, extension, and side bending. The vertebrae are small and the facet joints are oriented to permit a wide range of motion in multiple planes. In contrast, the thoracic region is constrained by the rib cage and the sagittal orientation of its joints, the lumbar region emphasizes stability for lifting and supports more limited rotation, and the sacrum is fused to the pelvis with minimal movement. Therefore, the neck region is the most mobile part of the spine.