Sacrum / Coccyx and L SPine

Flashcards for AP Lumbar Spine Radiography, covering patient positioning, central ray, central point, structures included, and technical factors.

What is the patient position for an AP Lumbar Spine X-ray?

Supine, straight on the table, nose to toes aligned, no rotation of pelvis or shoulders, knees flexed to reduce lordosis.

What is the Central Ray (CR) direction for an AP Lumbar Spine X-ray?

Perpendicular to the IR.

What is the Central Point (CP) for a lumbar AP

L3 + Midline

What structures should be included in a lumbar versus lumbosacral AP projection?

Lumbar: T12 to SI joints; Lumbosacral: T12 to full sacrum including SI joints.

Why are the knees flexed for an AP Lumbar Spine X-ray?

To reduce the lordotic curve and open intervertebral spaces.

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What is the patient position for a Lateral Lumbar Spine X-ray?

Left lateral, arms bent in front, knees bent, spine straight, no rotation.

What are the CR and CP for a Lateral Lumbar versus Lumbosacral X-ray?

CR: Perpendicular. CP Lumbar: L3 + mid-axillary line. CP Lumbosacral: L4 + mid-axillary line.

What structures are included in a Lateral Lumbar Spine X-ray?

T12 to proximal sacrum, posterior spinous processes.

What are the positioning indicators for a Lateral Lumbar Spine X-ray?

Superimposed posterior vertebral bodies, open intervertebral foramina (T12–L4), iliac crests nearly SI.

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What is the patient position for a Lateral L5/S1 Spot X-ray?

Lateral position, no movement from LAT LSPN.

What is the CR angulation for a Lateral L5/S1 Spot X-ray?

Males: 5° caudad; Females: 8° caudad.

What is the CP for a Lateral L5/S1 Spot X-ray?

2" posterior to ASIS and 1.5" inferior to iliac crest.

What structures are included in a Lateral L5/S1 Spot X-ray?

L5 and upper sacrum, including spinous process posteriorly.

What are the technical factors for a Lateral L5/S1 Spot X-ray?

KV: 85–90, SID: 100 cm, IR: Portrait, Resp: Suspend, AEC: Grid.

What is the obliquity angle for AP/PA Oblique Lumbar Spine X-rays?

45° rotation.

What is the CP for both AP & PA Oblique Lumbar Spine X-rays?

L3 (LCM). AP: 2" medial to raised ASIS. PA: 2" from midline toward raised side.

Which side is demonstrated in AP Oblique Lumbar Spine X-rays?

Side in contact with the table. RPO → Right side, LPO → Left side.

Which side is demonstrated in PA Oblique Lumbar Spine X-rays?

Raised side. RAO → Left side, LAO → Right side.

What structures are included in Oblique Lumbar Spine X-rays?

T12 to sacrum including SI joints and zygapophyseal joints.

What is the patient position for an AP Sacrum X-ray?

Supine, straight, legs extended, arms out of the way.

What is the CR angulation for an AP Sacrum X-ray?

15° cephalad (supine), 15° caudad (prone).

What is the CP for an AP Sacrum X-ray?

5 cm superior to PS or 2.5 cm below ASIS at the midline.

What structures are included in an AP Sacrum X-ray?

Entire sacrum, SI joints, L5–S1 joint space.

What are the positioning indicators for an AP Sacrum X-ray?

No SI of pubic bones, no sacral foreshortening, coccyx aligned with PS, symmetric ischial spines.

What are the technical factors for an AP Sacrum X-ray?

KV: 85–90, SID: 100–180 cm, Resp: Suspend, AEC: Grid/Non-grid.

What is the CR angle for an AP Coccyx X-ray?

10° caudad.

What is the CP for an AP Coccyx X-ray?

5cm superior to GT or 2.5 cm below ASIS.

What structures are included in an AP Coccyx X-ray?

Entire coccyx.

What are the technical factors for an AP Coccyx X-ray?

KV: 80–85, SID: 100–180 cm, Resp: Suspend, AEC: Grid/Non-grid.

What is the patient position for a Lateral Sacrum/Coccyx X-ray?

Lateral recumbent, hips and knees flexed, spine straight, use support under waist.

What are the CR and CP for a Lateral Sacrum versus Coccyx X-ray?

Sacrum: Perpendicular, 9 cm posterior to ASIS. Coccyx: 9 cm posterior and 5 cm inferior to ASIS.

What structures are included in a Lateral Sacrum and Coccyx X-ray?

Entire sacrum and coccyx.

What are the positioning indicators for a Lateral Sacrum and Coccyx X-ray?

Superimposed posterior margins of ilia and ischia.