CAMRT Radiography Practice Exam

When the patient is in which position is the right SI joint placed perpendicular to the IR?

1. Right lateral projection

2. 25-30 degree RAO

3. 25-30 degree RPO

4. 30-40 degree RPO

The correct answer is: 25-30 degree RAO

When the patient is in a 25-30 degree Right Anterior Oblique (RAO) position, the right sacroiliac (SI) joint is positioned to face directly towards the image receptor (IR). This positioning aligns the right SI joint in such a way that it is perpendicular to the plane of the IR, which is essential for obtaining an optimal image that clearly demonstrates the joint's detail. In this position, the rotation of the patient's body allows for a lateral perspective of the right SI joint, minimizing oblique angles that could distort the anatomy and pathology being assessed. Achieving the correct angulation is crucial for accurate radiographic interpretation and diagnosis, as it provides clear visualization of the right SI joint without superimposition of adjacent structures. The alignment in this specific oblique position is intentional, as it also aids in reducing the potential for motion artifacts and enhances the clarity of the outlines of the joint. Thus, the choice of a 25-30 degree RAO is effective in radiographic practices, especially when focusing on the anatomy of the SI joints.