Skull - AP Axial (Towne)

• Position the patient lying on their back or sitting upright, with the head centered and straight.
• Adjust the midsagittal plane (MSP) so it's aligned vertically and perpendicular to the image receptor.
• Position the orbitomeatal line (OML) perpendicular to the IR surface. If the patient cannot tuck the chin sufficiently, use the infraorbitomeatal line (IOML) instead, adjusting the tube angle accordingly.

Central Ray (CR)

• Angle the x-ray beam 30 degrees downward (caudad) when aligned with the OML.
• If using the IOML, increase the angulation to 37 degrees caudad.
• Direct the CR to a point about 2.5 inches above the eyebrows, aiming toward the base of the skull to pass through the foramen magnum.

Image Receptor

• Use a 10 x 12 inch (lengthwise) detector.
• Center it to the CR and align it perpendicular to the MSP.

Anatomy Visualized

• Provides a clear view of the occipital bone and posterior skull structures.
• Shows the dorsum sellae and posterior clinoid processes projected inside the foramen magnum, indicating proper head tilt and angulation.
• Displays the occipital condyles and lateral margins of the foramen magnum symmetrically.

Image Evaluation Criteria

• The petrous ridges and foramen magnum should be symmetrical, indicating no rotation.
• The dorsum sellae must appear centered and visualized within the foramen magnum.
• The entire skull should be visible, especially the vertex, without any cut-off, rotation or distortion.

Reserve Your Copy Today — The Röntgen Atlas: Volume One – Head

Release Date: November 8, 2025 | Price: $97

Includes newly captured positioning photos, diagnostic X-ray images, anatomical overlays, anatomy and physiology, and QR-linked video demonstrations for an enhanced student experience. 

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