Lumbar Spine - AP & Lateral

What are the essential projections for Lumbar Spine projections?

• AP and Lateral

• Lateral L5-S1

• AP oblique (RPO/LPO)

• AP axial lumbosacral (LS) junction and SI joints (Ferguson)

How to position a patient for an AP Lumbar Spine projection:

• shoulders and hips in same horizontal plane

• reduce lordosis; flexing hip and knees

Where is the central ray placed for an AP Lumbar Spine projection?

• perpendicular to IR

• for lumbosacral exams, enters patient at iliac crests (L4)

• for lumbar only, enters patient at 1½ inches above iliac crests (L3)

What is the collimation size for the AP Lumbar Spine projection?

• lumbosacral spine (including the sacroiliac joints), radiation field 8 × 17”

• lumbar spine only, radiation field can be reduced to 8 × 14”

What is the SID for the AP Lumbar Spine projection?

48” to reduce distortion and open the intervertebral disk spaces more completely

What is the Evaluation Criteria for the AP Lumbar Spine projection?

• area from the lower thoracic vertebrae to the sacrum

• x-ray beam collimated to the lateral margin of the psoas muscles

• no artifact across the mid-abdomen from any elastic in the patient’s underclothing

• symmetric vertebrae, with spinous processes centered to the bodies

• sacroiliac joints equidistant from the vertebral column

• open intervertebral disk spaces

What are the breathing instructions for the AP and Lateral Lumbar Spine projection?

suspend at the end of expiration

How to position a patient for the Lateral Lumbar Spine projection:

• recumbent or upright (same as for AP)

• knees flexed and superimposed

• arms, with elbows flexed, at right angle to body

• place radiolucent support under lower spine to place horizontal, if needed

Where is the central ray placed for the Lateral Lumbar Spine projection?

• perpendicular to IR

• enters patient on MCP at iliac crests (L4)

• if spine is not horizontal, angle caudad 5 degrees; 8 degrees for females

What is the collimation size for the Lumbar Spine projection?

• radiation field 8 × 17”

• use lead shield behind patient

What is the Evaluation Criteria for the Lumbar Lateral projection?

• lower thoracic vertebrae from coccyx to lumbosacral

• superimposed crests when the central ray is not angled

• open intervertebral disk spaces and foramina (L1-L4)

• spinous processes in profile

The Lumbar AP projection primarily visualizes the:

• lumbar vertebrae (L1-L5)

• open intervertebral disk space

The Lumbar Lateral projection primarily visualizes the:

• lumbar vertebrae (L1-L4)

• open intervertebral disk space