Extension to the orbit from paraorbital disease. The sinuses.

Disease of the sinuses frequently involves the orbit. Infection, mucocele, and tumor of the sinuses originally may present with orbital findings. Imaging attempts to evaluate the interface between sinus and orbit. Imaging findings reflect the integrity of the sinus mucosa, the thin bony wall, and the more resistant fibrous periorbita. Both CT and MR imaging play a role in this evaluation.