How is the central ray angle typically positioned for an AP axial projection?

In an AP axial projection, the central ray angle is generally directed at about 15 degrees cephalic. This positioning is specifically designed to achieve a clear view of the structures being imaged while minimizing distortion and superimposition of anatomical parts. By angling the central ray cephalically, the radiograph can better demonstrate the area of interest—commonly the hips or sacrum—by allowing visualization of the pelvic inlet, making it easier to assess any potential abnormalities without obfuscation from surrounding structures.

The cephalic angle is beneficial in positioning because it optimally aligns the X-ray beam with the plane of the anatomy being examined, resulting in a more accurate representation. This technique is foundational in radiography to enhance diagnostic quality, reducing the need for repeat images due to lack of visibility of key anatomical details.