Which form of sinusitis is most often associated with orbital cellulitis?

The most common form of sinusitis associated with orbital cellulitis is ethmoid sinusitis. This is primarily due to the anatomical proximity of the ethmoid sinuses to the orbit. The ethmoid sinuses are located between the nasal cavity and the orbits and have thin walls that can become eroded or allow for the spread of infection. When the ethmoid sinuses are infected, the infection can easily extend into the orbit, leading to orbital cellulitis.

Orbital cellulitis is an infection of the soft tissues surrounding the eye which can result from contiguous spread of infection from the sinuses. Ethmoid sinusitis is particularly concerning because it can lead to serious complications affecting vision and the overall health of the patient.

Maxillary sinusitis, frontal sinusitis, and sphenoid sinusitis can also theoretically lead to orbital complications, but they less frequently cause orbital cellulitis compared to ethmoid sinusitis. This is largely due to the structural barriers and the distance from these sinuses to the orbit compared to the ethmoidal region.