Question #384
The maxillary sinus
The maxillary sinus is a single large sinus, one on each side. It drains into the middle meatus, however, it extends below the lower margin of the nasal cavity so ciliary action is required to drain the mucus upwards. As a result, this sinus is more likely to get infected.
The frontal and ethmoidal sinuses are located near the frontal lobe of the brain – although infection is less common here, if it occurs it may result in a frontal abscess.
It lies above the upper molar teeth.
A tumour of the maxillary sinus may become so large that it blocks the nasolacrimal duct. The result is a condition known as epiphorea – the lacrimal sac is unable to drain so tears leak down the face.