The ethmoid sinuses, between the eyes, at the nasal bridge. The sphenoid sinuses, in bones behind the nasal cavity. The sinuses are lined with soft, pink tissue called mucosa. Normally, the sinuses ...

An endoscope with a camera attached also projects images of the sinuses on to a television screen while the procedure is carried out, so that the clinician can see what is happening.

The new technique uses X-rays of the frontal sinus, a large cavity behind the forehead which fills with mucus that drains into the nose, to determine the age of developing skulls.

Stage 3 is a fully developed frontal sinus, characterized by the two cavities merging and expanding. This tends to occur between the ages of 12 and 18, with a mean age of 16.