L-spine, sacrum, coccyx, SI joints

Positioning & technique for AP L-spine

• MSP to middle of IR

  • Knees flexed if recumbent

• CR:

  • @ Iliac crests for lumbosacral

  • 1.5” above iliac crest for lumbar

• 40” SID; 90 kVp @ 10 mAs

• 8×14 collimation

• No shielding - would cover anatomy of interest

• Breathing: Expiration, suspend breathing

• Marker

AP L-spine Evaluation

• Demonstrates T11/T12 to sacrum & SI joints

• Open intervertebral disk space

• Spinous process in the center

Positioning & technique for lateral L-spine

• MCP aligned to middle of IR

  • Knees & arms flexed if recumbent

• If recumbent, use sponge to make spine horizontal to IR

• CR:

  • @ iliac crest for lumbosacral

  • 1.5” above iliac crest for lumbar only

• No angle for normal pt. or when using sponge

• 5-8 caudal angle for wide pelvis & narrow thorax

• 40” SID; 96 kVp @ 28 mAs

• 8×14 collimation

• No shielding - would cover anatomy of interest

• Breathing: Expiration, suspend breathing

• Marker

Lateral L-spine Evaluation

• Vertebral bodies of T12 through S1

• Intervertebral disk spaces & pedicles

• Intervertebral foramina

• Vertebral bodies should appear boxlike

• Posterior rib & T12 are superimposed

• Rotation:

  • Border rims of vertebral bodies are not superimposed

Positioning & technique for lateral L5-S1 (spot)

• MCP aligned to middle of IR

  • Knees & arms flexed if recumbent

• If recumbent, use sponge to make spine horizontal to IR

• CR:

  • 1.5” inferior to iliac crest

  • 2” posterior to ASIS

  • If no sponge used > 5-8 caudal angle

  • Hypersthenic > 5-8 cephalic angle

• 40” SID; 96 kVp @ 45 mAs

• 8×8?

• No shielding - would cover anatomy of interest

• Breathing: Expiration, suspend breathing

• Marker

L-spine Spot Evaluation

• Vertebral bodies of L5-S1 well visualized

• L5-S1 intervertebral space

• Body of L5 boxlike

• Spine parallel to longitudinal axis of IR

• ASIS superimposed

• Bony trabeculae

Positioning & technique for posterior oblique L-spine

• Looking at downside zygapophyseal joint

• 45 degree angle for L3-L4

• 2 views for comparison (right & left)

• CR:

  • L3 or 1.5” above iliac crest & 2” medial to upside ASIS

• 40” SID; 90 kVp @ 18 mAs

• 8×14

• No shielding - would cover anatomy of interest

• Breathing: Expiration, suspend breathing

• Marker

Posterior L-spine Evaluation

• T12 to sacrum demonstrated

• Downside zygapophyseal joint

• “Scottie dogs” & open zygapophyseal joints

• Rotation indicated by pedicle:

  • No rotation: between the lateral & midline of vertebra

  • Over-rotation: closer to midline of vertebra

  • Under rotation: closer to lateral border of vertebra

Positioning & technique for anterior oblique L-spine

• Looking at upside zygapophyseal joint

• 45 degree angle for L3-L4

• 2 views for comparison (right & left)

• CR:

  • L3 or 1.5” above iliac crest & 2” medial to upside ASIS

• 40” SID; 90 kVp @ 18 mAs

• 8×14

• No shielding - would cover anatomy of interest

• Breathing: Expiration, suspend breathing

• Marker

Anterior L-spine Evaluation

• T12 to sacrum demonstrated

• Upside zygapophyseal joint

• “Scottie dogs” & open zygapophyseal joints

• Rotation indicated by pedicle:

  • No rotation: between the lateral & midline of vertebra

  • Over-rotation: closer to midline of vertebra

  • Under rotation: closer to lateral border of vertebra

Positioning & technique AP Axial Projection (Ferguson) Lumbosacral Junction

• MSP aligned to middle of IR

• CR:

  • Male: 30 degrees cephalic

  • Female: 35 degrees cephalic

  • 1.5” above pubic symphysis

• 40” SID; 90 kVp @ 14 mAs

• 8×14

AP Axial Projection (Ferguson) Lumbosacral Junction Evaluation

• L5-S1 (lumbosacral joint space)

Positioning & technique for AP/PA Axial Sacrum

• Supine w/ MSP in the middle of IR

• Shoulders on the same plane; ASIS on the same plane

• Support knees w/ sponge

• CR: 15 degrees cephalic; 2” above pubic symphysis

• 40” SID'; 90 kVp @ 14 mAs

• 8×7

• If PA, 15 degrees caudal to sacral curve

• No shielding - would cover anatomy of interest

• Breathing: Expiration, suspend breathing

• Marker

AP/PA Axial Sacrum Evaluation

• L5-S1 intervertebral disk space & superior rami of pubic bones included

• Bony trabeculae

• Sacrum centered

• Alae of sacrum symmetrical

Positioning & technique for Lateral Sacrum

• R or L lateral recumbent w/ MCP centered to IR

• Arms at right angle to body

• Flex hips & knees for comfort & balance & put a sponge in b/w knees

• CR: Center level w/ the ASIS & about 3.5” posterior to it

• 40” SID; 96 kVp @ 45 mAs

• 8×7

• No shielding - would cover anatomy of interest

• Breathing: Expiration, suspend breathing

• Marker

Lateral Sacrum Evaluation

• L5-S1 intervertebral disk space

• Entire lateral sacrum in the center

• Femoral heads & hips superimposed

• Short scale contrast

Positioning & technique for AP/PA Axial Coccyx

• Supine w/ MSP in middle of IR

• Shoulders on same plane; ASIS on same plane

• Support knees

• CR: 10 degrees caudal; 2” above pubic symphysis

• 40” SID; 85 kVp @ 14 mAs

• 4×4

• No shielding - would cover anatomy of interest

• Breathing: Expiration, suspend breathing

• Marker

AP/PA Axial Coccyx Evaluation

• Coccyx & distal 1/3 of sacrum

• Coccyx centered

• Coccyx directly above the symphysis pubis

Positioning & technique for Lateral Coccyx

Lateral Coccyx Evaluation

Positioning & technique for AP Axial Projection (Ferguson) L/S Junction & SI Joints

AP Axial Projection (Ferguson) L/S Junction & SI Joint Evaluation

Positioning & technique for AP Oblique Sacroiliac Joints

AP Oblique Sacroiliac Joints Evaluation