The nostrils are quite small, so even using a very bright halogen headlight and a dilator instrument (speculum) to expand the nostril, it is impossible to see any more than the front part inside the nasal cavity. The introduction of a small sterile rigid endoscope with an angled lens, or a sterile flexible endoscope whose tip can be manually rotated in various directions, allows a very detailed inspection of the whole of the nasal cavity and the site of the sinus openings. Further back the nasopharynx and Eustachian tube openings can also be examined.
Cophenylcaine, a surface local anaesthetic and decongestant, is sprayed into each nostril held open by a dilator speculum. This drug is absorbed very quickly and numbs and shrinks the nasal lining. Although the introduction of an endoscope is an unusual feeling it is not unpleasant. The subsequent examination will take less than 5 minutes.