Lateral Cervical (Flexion) is a radiography positioning projection of the Spine. Erect lateral, head flexed forward, CR to C4. The centering point is located c4 vertebra with head flexed toward chest.. The central ray is perpendicular to ir at c4 level.. Image-quality criteria include cervical vertebrae aligned in flexed position., intervertebral disc spaces symmetrically open.. Standard exposure ranges from 75 to 85 kVp, 10 to 20 mAs, at an SID of 72 inches (180 cm).
Anatomy demonstrated
- Cervical vertebrae C1-C7 in flexion.
- Intervertebral disc spaces under flexion stress.
- Anterior longitudinal ligament stretch.
- Spinous process separation.
- Cervical spine lordosis change.
Patient preparation
- Verify patient identity using two identifiers.
- Remove neck jewelry and radiopaque objects.
- Erect lateral posture with shoulders relaxed.
- Gently flex head to bring chin toward chest.
- Voluntary motion only, no forced flexion.
Position & centering point
C4 vertebra with head flexed toward chest.
Central ray
Perpendicular to IR at C4 level.
Exposure / technique
- kVp
- 75–85
- mAs
- 10–20
- SID
- 72" (180 cm)
- Notes
- Flexion position. Patient voluntary motion, not forced.
Image-quality criteria
- Cervical vertebrae aligned in flexed position.
- Intervertebral disc spaces symmetrically open.
- Spinous processes show flexion curve.
- All cervical vertebrae C1-C7 included.
- Soft tissue outline visible.
Common errors / ARRT traps
- 1 Forced flexion causes patient pain and artifact.
- 2 Insufficient flexion does not demonstrate true motion.
- 3 Rotation or obliquity prevents accurate assessment.
- 4 CR not centered to C4 misses disc space changes.
Clinical indications
- Evaluation of cervical range of motion.
- Assessment of atlantoaxial instability.
- Suspected ligamentous injury evaluation.
- Post-injury functional assessment.
Aligned to the 2025 ARRT Content Specifications.