The frontal sinus are pockets of space located above the orbit of each eye in the frontal bone. They are lined with mucus membrane. The size and shape of the frontal sinus can vary from person to person. These spaces fill up with mucus, which then drain into the nose. The draining process can be hindered by blockages, which often causes an inflammation of the frontal sinus. As mucus accumulates, this can cause infections. Bacterial or viral infections located in either the frontal sinus, or the paranasal sinus, cause what is known as sinusitis. Sinusitis is the inflammation of the sinuses. When there are blockages from the sinuses to the nasal passages, sinusitis is likely to occur. Nasal polyps can also cause sinusitis in the frontal sinus. Nasal polyps are caused my recurring inflammation of the sinuses. They resemble small non-cancerous sacs, and are found in the sinuses or nasal passageways. Nasal polyps do not always cause problems, but they do when they become particularly enlarged, blocking the flow of mucus.
Written and medically reviewed by the Healthline Editorial Team
In Depth: Frontal sinus