Inferior turbinate is a separate bone attached to the maxilla. Each turbinate

overhangs a channel or meatus corresponding in length to the turbinate beneath

which it is situated. All three reach forwards from the posterior aperture of

the nose, called the posterior naris or choana. The superior meatus is confined

to the posterior third of the lateral wall of the nasal cavity; the middle

meatus runs forward about two-thirds of its length; and the inferior meatus

extends the whole length of the lateral wall of the cavity. The space above the

superior turbinate is called the spheno-ethmoidal recess. Between the three

turbinates and the nasal septum, which separates the two nasal cavities, is a

space called the general nasal meatus.

The meatuses are of clinical importance in respect of their contents. The

nasolacrimal canal opens into the anterior end of the inferior meatus.

Communication between the paranasal sinuses and the nasal cavity takes place

through openings, or ostia. The frontal, anterior ethmoidal and maxillary

sinuses open into the middle meatus; the posterior ethmoidal sinuses drain into

the superior meatus; the sphenoidal sinus communicates with the superior meatus.

The middle meatus contains several structures of importance (Fig. 19, 23). An

enlargement is found at the anterior end of the middle meatus, which is part of

the ethmoid bone , known as the unciate process. A little farther back can be

seen another eminence which is called the bulla ethmoidalis, which represents a

protrusion into the meatus of one air cells of the ethmoidal labyrinth.

In the normal nose these parts can rarely be seen from the front. Between these

two enlargements is a groove which is known as the hiatus semilunaris, into

which the ostium of the maxillary sinus opens. The hiatus semilunaris, when

followed upwards, leads to a narrowing called the infundibulum. In many cases

the infundibulum continues upwards becoming the fronto-nasal duct. Owing,

however, to the irregularity of the development of the frontal sinus and the

anterior ethmoid cells, it is possible that the fronto-nasal duct may open from

an anterior ethmoid cells.

The nasal septum separates the two nasal cavities and is partly osseous and

partly cartilaginous. The perpendicular plate of the ethmoid and the vomer bone

constitute the upper and posterior part, while the septal cartilage completes

the septum anteriorly, stretching from the dorsum of the nose above to the nasal

crests of the maxillary and palatine bones below. The main arterial supply of

the nasal septum arises from the septal branch of the sphenopalatine artery

(maxillary a.- E.C.A.), and this anastomoses with the greater palatine artery

(maxillary a.- E.C.A.), septal branches of the superior labial (facial a.-

E.C.A.), anterior ethmoidal (ophthalmic a.- I.C.A.) and posterior ethmoidal

(ophthalmic a.- I.C.A.) arteries at the antero-inferior part of the septum, or

Little’s (Kiesselbach’s) area (Fig. 20), which is of importance in epistaxis.

The lateral nasal wall is supplied by lateral branches from these vessels.

Venous drainage from the nasal cavity is through the sphenopalatine foramen to

the pterygoid plexus, but some veins join the superior ophthalmic vein in the

orbit, while others enter the anterior facial vein. Lymphatic vessels from the

anterior part of the cavity join cutaneous lymphatics to the submandibular

glands, and so to the superior deep cervical glands. Posteriorly the lymphatic

drainage is to the medial deep cervical glands.

The nasal mucous membrane consists of a layer of fairly dense connective tissue

containing large blood vessels and some unstriped muscle fibres. There is

erectile or cavernons tissue comprising irregular thin-walled blood spaces in

the anterior and posterior ends of the inferior turbinate. A layer of elastic

tissue fibres is present beneath the basement membrane, and this layer allows

the mucosa to return to normal size when the vascular engorgement of the

erectile tissue has worn off. The surface epithelium is columnar ciliated lying

upon several layers of cuboidal cells resting upon the basement membrane. There

are many mucous glands beneath the basement membrane, their ducts penetrating

the membrane to open on the surface.

There are two nerve supplies to the nasal cavity - sensory and secretory. The

main sensory nerve supply is derived from the maxillary division of the

trigeminal nerve through branches arising in the pterygopalatine ganglion. The

lateral and medial internal nasal branches of the ophthalmic division of the

trigeminal nerve supply the anterior part of the nasal cavity, while the floor

and anterior end of the inferior turbinate are served by the anterior dental

branch of the infra-orbital nerve (maxillary division of the trigeminal nerve).

Secretory nerve fibres supplying the glands and unstriped muscle belong to the

sympathetic and parasympathetic systems. Sympathetic fibres, which produce