AAO-HNSF Primary Care Otolaryngology Handbook

CHAPTER 10

The Osteomeatal Complex The most significant area to examine in a patient with sinus complaints is the osteomeatal complex (OMC) . Coronal CT scans are used in the evaluation of sinus disease because they are best for visualizing the OMC. The OMC is the region through which the maxillary, ethmoid, and frontal sinuses drain in the nose. An obstruction of the OMC will frequently lead to sinusitis and is often caused by mucosal edema or anatomic abnormalities. Neoplasm should always be on the differential diagnosis. The anterior-most ethmoid sinus—the agger nasi cell —is frequently clouded. Edema in this sinus may be associated with obstruction of the nasal frontal duct and results in frontal sinusitis. This area is best visualized on a sagittal CT scan. In most instances, sinusitis is manifested by loss of aeration of multiple sinuses, usually involving both sides. This is visible as water density, which may be swelling of the mucosa, polyps, fluid, or pus. Clouding of a single sinus (unilateral disease) suggests an unusual cause, such as a tumor. Remember: The best way to learn to look at any x-ray or imaging study is to care- fully and systematically examine as many as possible.

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Figure 10.1. A coronal CT scan of the sinuses in a patient with deviated nasal septum and an air cell (concha bullosa) within the right middle turbinate. The surgical correction of nasal obstruction in this patient would require partial middle turbinectomy, as well as correction of the deviated nasal septum.

Figure 10.2. A coronal CT scan of the sinuses demonstrating complete opacification of the nasal cavity and ethmoid and maxillary sinuses. This image represents pansinusitis with polyps; however, neoplasms may present in a similar fashion.

Primary Care Otolaryngology