Coronal images reveal projection of the sphenoid sinus sidewall beyond the foramen rotundum (r). The lateral recess extends into the greater wing of the sphenoid bone above the vidian canal (v) and below the foramen rotundum (r), separating the two. There may be normal side-to-side asymmetry of the vidian-rotundum distance.
The main differential consideration in an opacified sinus is an expansile or erosive process in the sphenoid sinus (e.g., mucoceles or polyps). The most specific evidence of such a process is gross sinus wall erosion and flattening or erosion of the rims of vidian canal or the foramen rotundum.
The patient above has bilateral lateral recesses, with the one on the right extending to the sphenoid wing. The patient also has multiple facial fractures.
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