What makes up the nasal septum on a radiograph?

• A. The dorsum of the nasal bone and the frontal sinus.
• B. Superimposition of septal cartilage and the vomer.
• C. The ethmoid bone and the sphenoid bone.
• D. The nasal conchae and the palatine bone.

Answer: (B)

On a radiograph, the nasal septum is seen where the boundary between the two nasal cavities lies, and because septal cartilage doesn’t show up well on X-ray, the septum’s appearance is created by the bone of the vomer with the overlying septal cartilage. The cartilage is radiolucent, so the visible line corresponds to the superimposed structure of the vomer plus the cartilage. Anatomically, the septum includes the perpendicular plate of the ethmoid and the vomer, but on radiographs the boundary you observe is the combination of the vomer with the overlying cartilage, which is why that option is the best description.