What is the shape of the maxillary sinuses in the posteroanterior (PA) projection?

The shape of the maxillary sinuses in the posteroanterior (PA) projection is typically described as pyramidal. This is primarily due to their location and the anatomical structure of the maxilla, which is situated laterally to the nasal cavity.

In a PA projection, the maxillary sinuses usually appear with a broad base that faces the lateral aspect and a pointed apex towards the midline under the orbit of the eye. This pyramidal shape is significant when it comes to imaging and diagnosing various conditions of the sinuses, as it directly affects how the sinuses are visualized during radiographic examinations.

Understanding this shape also informs clinicians about potential pathologies and is essential for interpreting imaging results accurately. The distinct pyramidal structure allows for more tailored approaches in both diagnosis and potential therapeutic measures when dealing with sinus-related issues.