RTE 122 Sacroiliac Joints Flashcards

Questions and Answers

What are the projections used for Sacroiliac joints?

AP/PA axial (Ferguson) - Bi Lateral

AP oblique RPO/LPO

PA oblique RAO/LAO

All of the above (correct)

AP/PA axial are which method?

Ferguson method

What is the IR size/collimation for AP/PA axial projection of SI joints?

8x10 or 10x12 lengthwise

How is the patient positioned for AP axial projection?

Supine, midsagittal plane centered to grid, legs extended, pelvis not rotated Signup and view all the answers

Where should the central ray be located on AP axial projection?

1 1/2" superior to pubic symphysis on midsagittal plane Signup and view all the answers

What are the evaluation criteria for AP axial SI joints?

Lumbosacral joint, and both SI joints symmetrical and free of superimposition Signup and view all the answers

What is noted about PA axial?

PA axial possible with a prone position, central ray 35° caudad Signup and view all the answers

What other anatomy has the same criteria as AP/PA axial SI joint projections?

Lumbosacral junction Signup and view all the answers

What is the IR size/collimation for AP oblique RPO/LPO SI joint?

8x10 or 10x12 lengthwise, collimated to 6x10 or 6x12 Signup and view all the answers

What is the position of the patient for AP oblique RPO/LPO SI joint?

Supine, head on firm pillow Signup and view all the answers

What is the position of part for AP oblique RPO/LPO SI joint?

Shoulder, thorax and thigh supported with foam Signup and view all the answers

Where does the central ray enter for AP oblique RPO/LPO SI?

Perpendicular to center of IR, 1" medial of the elevated ASIS Signup and view all the answers

What are the evaluation criteria for AP oblique RPO/LPO SI joint?

Proper collimation, open SI joint space, minimal overlapping of ilium and sacrum Signup and view all the answers

How are oblique SI joint exams compared?

By taking 2 x-rays depending on side of interest Signup and view all the answers

What is the position of the patient for PA oblique RAO/LAO SI joint?

Patient semiprone, side being examined closest to IR Signup and view all the answers

What is the position of part for PA oblique RAO/LAO SI joint?

MCP 25-30° to table, check for rotation Signup and view all the answers

Where does the central ray enter for PA oblique RAO/LAO SI?

Perpendicular to IR, 1" medial to ASIS closest to IR Signup and view all the answers

What are the evaluation criteria for PA oblique RAO/LAO SI joint?

Proper collimation, open SI joint space, minimal overlapping of ilium and sacrum Signup and view all the answers

What is the patient dose/protection with SI joint exams?

Shielding of gonads if possible, tight collimation Signup and view all the answers

Study Notes

Projections for Sacroiliac Joints

AP/PA axial, Ferguson method (bi-lateral), AP oblique RPO/LPO, PA oblique RAO/LAO are used for imaging sacroiliac joints.

AP/PA Axial Method

AP/PA axial projections utilize the Ferguson method.

Image Receptor Size

Use 8x10 or 10x12 inches lengthwise for AP/PA axial projection of sacroiliac joints.

Patient Positioning for AP Axial

Patient is supine with the midsagittal plane centered to the grid, legs extended, and pelvis not rotated.

Central Ray Location for AP Axial

Central ray is positioned 45° cephalad (average: 30° for males, 35° for females), 1.5 inches superior to the pubic symphysis on the midsagittal plane.

Evaluation Criteria for AP Axial

Lumbosacral joint and both SI joints should appear symmetrical and free from superimposition, with a clear open intervertebral space between L-5 and S-1.

Notes on PA Axial

PA axial can be performed in a prone position with the central ray at 35° caudad entering at the L-4 spinous process; other recommended techniques involve perpendicular rays entering 2 inches distal to the L-5 spinous process.

Anatomy with Similar Criteria

The lumbosacral junction shares imaging criteria with AP/PA axial SI joint projections.

Image Receptor Size for AP Oblique RPO/LPO

Use 8x10 or 10x12 inches lengthwise, collimated to 6x10 or 6x12 inches for AP oblique RPO/LPO SI joint.

Patient Positioning for AP Oblique RPO/LPO

Patient remains supine, supported by a firm pillow under the head.

Positioning of Part for AP Oblique RPO/LPO

The side being examined is positioned farthest from the table; MCP is placed 25-30° to the table, with shoulders, thorax, and thigh supported. Center the sagittal plane 1 inch medial to the affected ASIS to the grid, checking for back rotation.

Central Ray for AP Oblique RPO/LPO

Central ray enters perpendicular to the center of the IR, 1 inch medial of the elevated ASIS.

Evaluation Criteria for AP Oblique RPO/LPO

Ensure proper collimation, an open SI joint space, and minimal overlapping of ilium and sacrum for a well-centered joint on the radiograph.

Comparison of Oblique SI Joint Exams

Two x-rays are taken based on the side of interest: Left side uses AP RPO followed by PA LAO, and right side uses AP LPO followed by PA RAO.

Patient Positioning for PA Oblique RAO/LAO

Patient is in a semiprone position with the side of interest closest to the IR; flex the forearm and knee on the elevated side for support, using a small pillow under the head.

Positioning of Part for PA Oblique RAO/LAO

The side of interest is closest to the table; MCP at 25-30° to the table. Center the body so a point 1 inch medial to the ASIS closest to the IR is aligned with the grid.

Central Ray for PA Oblique RAO/LAO

Central ray is perpendicular to the IR and centered 1 inch medial to the closest ASIS.

Evaluation Criteria for PA Oblique RAO/LAO

Proper collimation, open SI joint space, minimal overlapping of ilium and sacrum, and well-centered joint on the radiograph are essential parameters.

Patient Dose/Protection

Gonadal shielding is recommended when possible, alongside tight collimation to minimize exposure.

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Description

Test your knowledge on the positioning of sacroiliac joints with these flashcards. Each card covers key projections, methods, and patient positioning. Perfect for RTE 122 students looking to reinforce their understanding of radiographic techniques.