Surgical anatomy of the nose

The supporting structures of the nose are shown in Fig. 39.1. The paired nasal bones join in the midline with a suture and are supported by the septum, which consists of the anterior quadrilateral cartilage, the perpendicular plate of the ethmoid and the vomer (Fig. 39.2). In children the length of the nasal bone equals its width, whereas in the adult the length is three times the width. The lateral wall of the nasal cavity contains the superior, middle and inferior turbinates (Fig. 39.3). Opening on to the lateral nasal wall are the ostia of all the nasal sinuses except for the sphenoid sinus (Fig. 39.4). The nasolacrimal duct opens into the inferior meatus beneath the inferior turbinate approximately 3 cm posterior to the external nasal opening. Below the middle turbinate is the middle meatus into which the nasofrontal duct, the anterior ethmoid cells and the maxillary antrum open (Fig. 39.5). The superior meatus between the middle and superior turbinates contains the opening for the posterior ethmoid cells. The sphenoid ostium lies at this level on the anterior wall of the sphenoid sinus. The nasal cavities and sinuses are lined by respiratory epithelium. The olfactory mucosa, innervated by fibres from the olfactory nerve, lines the area of the olfactory cleft and the cribriform plate. The nasal fossae and sinuses receive their blood supply via the external and internal carotid arteries. The external carotid artery supplies the interior of the nose via the maxillary and sphenopalatine arteries. The greater palatine artery supplies the anteroinferior septum via the incisive canal. The contribution from the internal carotid artery is via the anterior and posterior ethmoidal arteries which are branches of the ophthalmic artery (Fig. 39.6). All of these arteries anastomose to form a plexus of vessels (Kiesselbach’s plexus) on the anterior part of the nasal septum. Venous drainage is via the ophthalmic and facial veins and the pterygoid and pharyngeal plexus. Intracranial drainage into the cavernous sinus via the ophthalmic vein is of particular clinical importance because of the potential for intracranial spread of nasal sepsis. The nasal cavity and sinuses have a sensory nerve supply provided by the first and second branches of the trigeminal nerve. The olfactory epithelium is supplied by the olfactory nerve. Autonomic innervation comprises sympathetic fibres to the blood vessels via the cervical and pterygopalatine ganglia. Parasympathetic fibres also synapse in the pterygopalatine ganglion before passing to the mucous glands.