In which projection of the skull is the dorsum sellae found within the foramen magnum?

In the AP axial skull projection using the Towne method, the dorsum sellae is visualized within the foramen magnum. This specific projection is designed to define the occipital region of the skull and to provide an optimal view of the foramen magnum.

When the patient's orbitomeatal line (OML) is properly positioned at an angle of 30 degrees or the infraorbitomeatal line (IOML) at an angle of 37 degrees towards the imaging receptor, it enables the x-ray beam to enter at the upper margin of the external occipital protuberance and directs it toward the foramen magnum. As a result, this angulation allows the dorsum sellae, which is part of the sella turcica and positioned posteriorly on the sphenoid bone, to be effectively centered in the foramen magnum on the radiograph.

This anatomical feature is crucial for evaluating cranial and cervical spine relationships and facilitates diagnosis of pathological conditions. The accurate positioning in this projection highlights the relationship of the cranial structures and makes it easier to assess for any abnormalities.

The other projections do not centralize this area in the same way; for example, the lateral skull projection