12. The nose and sinuses

The external nose determines facial appearance to a large extent. Position, shape and size are important here and easy to examine. Patency is also important: this is determined by the position of the nasal septum, the thickness of the conchae and the nasal mucosa. A headlight is used for this examination, known as ‘anterior rhinoscopy’. The paranasal sinuses terminate in the lateral nasal wall. The mucus produced there flows through the ostia to the rear of the nose, moved by cilia. The paranasal sinuses can only be examined to a limited extent: endoscopy or X-ray examination will be required. The nose is highly vascularised, hence wounds usually heal well, but the good perfusion can make nose bleeds (epistaxis) severe. Smell is captured high in the nose by small nerve endings: these are branches of the olfactory nerve (N I) that pass through the lamina cribrosa (of the ethmoid bone).