chapter  2
22 Pages

Nose

ByMarie Lyons

The nose is a pyramidal structure formed from bone and cartilage. It is divided into two nares (nostrils) by the septum, which itself consists of bony and cartilaginous parts. Each nostril has a floor, a roof, a straight medial wall and a sloping lateral wall. The posterior part opens into the nasopharynx via a posterior choanae. The floor of the nose is formed by the palate, mainly the hard palate (this is why it is always vital to look in the mouth when examining the nose, as the floor of the nose is the roof of the mouth). The roof is formed from the cribiform plate and is pierced by the olfactory nerve. This is why it is necessary to sniff in order to smell things properly, as doing so allows olfactory epithelium to be exposed to odour ‘molecules’. The lateral walls consist of nasal mucosa covering tiny bones called conchae or turbinates. These increase the surface area of the nose and allow the air to be warmed and moistened on inhalation. The edge of the nostril also has hairs (vibrissae) that trap dust. The nose is very well supplied with blood vessels from both the external and internal carotid systems. The external carotid system supplies blood mainly via the sphenopalatine branch of the maxillary artery. There are also branches from the labial artery. The anterior ethmoidal artery is a branch of the internal artery, and is the artery that is sometimes damaged in nasal fractures.46