Osteomeatal Unit Obstruction

The osteomeatal unit is the part of the middle meatus that drains the frontal and maxillary sinuses and anterior and middle ethmoid air cells. When it is obstructed these sinuses characteristically become inflamed, known as the osteomeatal pattern. In this patient they are completely opacified on the right. Middle meatal lesions that may obstruct the osteomeatal unit include mucosal inflammation, ipsilateral concha bullosa, severe septal deviation, and nasal polyps and tumours. This patient incidentally has a concha bullosa in the middle turbinate on the left.
Reference: Harnsberger HR. Handbook of Head and Neck Imaging, 2nd edition, Mosby 1995
Credit: Dr Donna D'Souza
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