A cervical X‑ray with flexion and extension obtains neck X‑rays while you bend your head forward and backward. Comparing these views shows how vertebrae move, revealing instability, abnormal motion, ligament injury or post‑surgical fusion failure. It’s used for trauma, chronic neck pain or neurological symptoms. The test is quick and generally safe, though movement may be uncomfortable and is done under radiographer instruction.

Flexion and extension of the cervical spine are sagittal-plane movements: flexion brings the chin toward the chest (forward bending), while extension lifts the chin and tilts the head back (backward bending). These motions occur mainly at the lower cervical segments (C4–C7) and the occiput–C1, enabling nodding and gaze adjustments and are limited by ligaments, discs, and facet joints.

The lateral view is the single most useful cervical spine x-ray because it shows vertebral alignment, vertebral bodies, disc spaces and prevertebral soft tissues from C1 to C7. In trauma or suspected instability, a series is standard — lateral plus AP, open‑mouth (odontoid) and oblique views — to evaluate the odontoid, neural foramina and detect occult fractures.

A standard cervical spine X‑ray typically uses three views: lateral, anteroposterior (AP) and an odontoid (open‑mouth) view. In many centers, the three‑view series is routine for initial assessment. Additional views — bilateral obliques, swimmer’s view, or flexion‑extension films — may be added for trauma, foraminal evaluation, or instability, raising the total to four to six films.

Flexion and extension views are specialized spinal X‑rays taken while the patient bends forward (flexion) and backward (extension). They assess dynamic spinal alignment and intervertebral motion to detect instability, ligamentous injury, spondylolisthesis or failed fusion that may not appear on neutral images. They are performed under supervision and require patient cooperation to safely obtain useful diagnostic information.

Have the patient sit upright with a neutral spine. Use a goniometer or inclinometer: place the fulcrum over the external auditory meatus, the stationary arm vertical (perpendicular to the floor) and the movable arm aligned with the nose/chin. Ask the patient to flex (chin to chest) and extend (look up); record end-range angles. Repeat three times and average. Normal ≈45° each.