An air-filled hollow in the facial or cranial bones, communicating with the nasal cavity.
One of the four pairs of sinuses in the skull near the nose, which open into the nasal cavity and are lined with sticky mucus.
Any of several air cavities in bones around the nose. More commonly referred to as nasal sinuses.
Sinus cavities located directly adjacent to the nasal passage.
Sited within some of the bones of the skull, these are spaces filled with air and lined by mucous membrane. The sinuses comprise frontal and maxillary (a pair of each), ethmoidal (a group of small spaces), and two sphenoid sinuses. They drain into the nasal cavities. When a person has an upper respiratory infection, the sinuses sometimes become infected: this causes pain, purulent discharge from the nose and obstruction of the nasal passages Generally all that is required is a decongestant and antibiotic but, occasionally, infection may spread to produce a cerebral abscess or cerebral venous sinus thrombosis.
One of the air cavities in the frontal, maxillary, sphenoid, or ethmoid bones. The anterior group consists of the frontal, maxillary, and anterior ethmoids; the posterior group includes the posterior ethmoids and sphenoid. These sinuses develop embryologically from nasal cavities, are lined with the same type of ciliated epithelium, are filled with air, and communicate with nasal cavities through their various ostia. They lighten the skull, being lighter than dense bone, and are resonating chambers for the voice.