Study of the relationship between sphenoid sinus volume and protrusions in the sphenoid sinus

which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. In accor-dance of the Creative Commons Attribution License all Copyrights © 2014 are reserved for SCIRP and the owner of the intellectual property Yuefeng Li et al. All Copyright © 2014 are guarded by law and by SCIRP as a guardian. The relationship between the volume of sphenoid sinus (SS) and the prevalence of internal carotid artery (ICA) and optic nerve (ON) protrusions in the SS was studied by using high-resolution CT imaging. The ICA and ON protrusions in SS were observed in randomly selected normal head CT scanning images from 350 adult subjects. Ac-cording to the incidence of ICA protrusion, three groups were divided into no ICA protrusion (70.75%), unilateral protrusion (8.68%) and bila-teral protrusions (20.57%). The ON protrusio