Coronal CT of sinuses (normal ). There is normally a sharp, distinct border ... The maxillary sinus ostium is completely obstructed by grey area representing swollen tissue.

The maxillary sinus drains into the nose through a hole called the ostia.When the ostia becomes clogged, sinusitis can occur. The ostia of the maxillary sinus often clog because the ostia are ...

Sinusitis occurs as a result of obstruction of the osteomeatal unit, which is located in the vicinity of the maxillary sinus ostium (Fig. 1). Because of obstruction, mucus accumulates inside the ...