Lateral Lumbar is a radiography positioning projection of the Spine. Lateral recumbent, knees flexed, CR perpendicular to the iliac crest (L4). The centering point is located at the level of the iliac crest (l4).. The central ray is perpendicular to ir at the level of the iliac crest (l4).. Image-quality criteria include all lumbar vertebrae l1-l5 clearly visualized., intervertebral disc spaces open symmetrically.. Standard exposure ranges from 90 to 100 kVp, 50 to 100 mAs, at an SID of 40 inches (102 cm).
Anatomy demonstrated
- Lumbar vertebral bodies L1-L5.
- Intervertebral disc spaces.
- Lumbar spinous processes.
- Facet joints of lumbar spine.
- Lumbar spinal canal in profile.
Patient preparation
- Verify patient identity using two identifiers.
- Remove jewelry, belt, and radiopaque objects.
- Lateral recumbent position, true lateral alignment.
- Hips and shoulders perpendicular to IR.
- Knees flexed for patient comfort.
Position & centering point
At the level of the iliac crest (L4).
Central ray
Perpendicular to IR at the level of the iliac crest (L4).
Exposure / technique
- kVp
- 90–100
- mAs
- 50–100
- SID
- 40" (102 cm)
- Notes
- Knees flexed for patient comfort and stability.
Image-quality criteria
- All lumbar vertebrae L1-L5 clearly visualized.
- Intervertebral disc spaces open symmetrically.
- Vertebral bodies superimposed without rotation.
- Spinous processes aligned posteriorly.
- Lumbar lordotic curve demonstrated.
Common errors / ARRT traps
- 1 Rotation shifts vertebral bodies creating offset illusion.
- 2 Straightened legs increase lordosis and close disc spaces.
- 3 CR not at L3 misses mid-lumbar vertebrae.
- 4 Pelvic rotation tilts vertebral alignment.
Clinical indications
- Lumbar spine trauma evaluation in lateral patient.
- Assessment of vertebral alignment and disc height.
- Evaluation of disc herniation and canal stenosis.
- Post-operative lumbar fusion follow-up.
Aligned to the 2025 ARRT Content Specifications.