Lateral Cervical (Extension) is a radiography positioning projection of the Spine. Erect lateral, head extended backward, CR to C4. The centering point is located c4 vertebra with head extended backward.. The central ray is perpendicular to ir at c4 level.. Image-quality criteria include cervical vertebrae aligned in extended 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 extension.
- Intervertebral disc spaces under extension stress.
- Posterior longitudinal ligament.
- Facet joint alignment in extension.
- Cervical lordosis increase.
Patient preparation
- Verify patient identity using two identifiers.
- Remove neck jewelry and radiopaque objects.
- Erect lateral posture with shoulders relaxed.
- Gently extend head backward, eyes looking up.
- Voluntary motion only, no forced extension.
Position & centering point
C4 vertebra with head extended backward.
Central ray
Perpendicular to IR at C4 level.
Exposure / technique
- kVp
- 75–85
- mAs
- 10–20
- SID
- 72" (180 cm)
- Notes
- Extension position. Patient voluntary motion, not forced.
Image-quality criteria
- Cervical vertebrae aligned in extended position.
- Intervertebral disc spaces symmetrically open.
- Spinous processes show extension curve.
- All cervical vertebrae C1-C7 included.
- Soft tissue outline visible.
Common errors / ARRT traps
- 1 Forced extension causes patient pain and motion artifact.
- 2 Insufficient extension does not demonstrate true motion.
- 3 Rotation or lateral flexion prevents accurate assessment.
- 4 CR not centered to C4 misses disc space changes.
Clinical indications
- Evaluation of cervical range of motion.
- Assessment of facet joint loading in extension.
- Suspected nerve compression in extended position.
- Post-injury functional cervical assessment.
Aligned to the 2025 ARRT Content Specifications.