2 Nose, Nasal Sinuses, and Face

Applied Anatomy and Physiology

■ Basic Anatomy

■ External Nose

The supporting structure of the nose consists ofbone, cartilage, and connective tissue. Figure 2.1shows the most important elements. The bonysuperior part of the nasal pyramid is often broken

in typical fractures of the nasal bones, but it mayalso be fractured in injuries to the central part of theface. The cartilaginous inferior portion is less at risk,at least in mild blunt trauma, because of its elasticstructure, but it is endangered in stab wounds,lacerations, and gunshot injuries. The shape, posi-tion, and properties of the bone and cartilage of thenose have a considerable influence on the shapeand esthetic harmony of the face (see p. 212) andon the function of the nasal cavity.

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Fig. 2.1 The nasal skeleton.1, Glabella; 2, nasal bone;3, lateral nasal cartilage;4, cartilaginous nasal septum;5, alar cartilage with lateral (a)and medial crus (b); 6, nasalvalve between the cranial alarand caudal lateral cartilages.R, Rhinion. The bony portionof the nose is completely rigid.The flexible cartilaginous por-tion begins at the rhinion. Thedistal caudal lateral cartilagescan move like the wings of abutterfly, whereas the alarcartilages move more like thewings of a bird. The nasal sep-tum is the center of stability.

aus: Behrbohm u. a., Ear, Nose, and Throat Diseases (ISBN 9783136712030) © 2009 Georg Thieme Verlag KG

The following blood vessels in the external noseare of practical importance:● Facial artery and its branches.● Dorsal nasal artery, arising from the ophthalmic

artery.

Profuse hemorrhage can arise from these vesselswhen the central part of the face is injured.

The angular vein is also clinically important.Thrombophlebitis arising from a furuncle of theupper lip or the nose can spread via the ophthalmicvein to the cavernous sinus, causing a cavernoussinus thrombosis (see p. 189 and Fig. 2.2).

The external nose derives its sensory nerve sup-ply from the first and second branches of the tri-geminal nerve (see Fig. 2.15a, b). The muscles de-rive their motor nerve supply from the facial nerve.

■ Nasal Cavity

The interior of the nose is divided by the nasalseptum into two cavities,which are usually unequalin size. Each side may be divided into the nasalvestibule and the nasal cavity proper (Fig. 2.3a, b).The nasal vestibule is covered by epidermis con-taining hairs (vibrissae) and sebaceous glands. Thelatter are the site of origin of a nasal furuncle, whichcan thus only develop in the nasal cavity in thevestibule.

The medial wall of the nasal vestibule encloses the sup-porting structure of the anterior part of the cartilaginousseptum and the membranous septum—i. e., the columella.The roof of the vestibule is formed by the bird wing–shaped

lower lateral or alar cartilage, the medial crus of whichextends into the columella and the lateral crus of whichsupports the external wall of the vestibule (Figs. 2.1, 2.3a,b). The alar cartilage determines the shape of the nasal tipand the nasal apertures. Correcting this area is often animportant part of rhinoplasty.

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Fig. 2.2 Important vascular relationships in the face.1, Sitefor ligation of the angular vein; 2, facial artery; 3, facial vein;4, common carotid artery; 5, internal jugular vein; 6, pter-ygoid plexus; 7, sigmoid sinus; 8, inferior sagittal sinus;9, superior sagittal sinus; 10, cavernous sinus; 11a, superiorpetrosal sinus; 11b, inferior petrosal sinus.

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Fig. 2.3a, b a Section throughthe anterior nose, showing thevestibule and the limen nasi. Thedashed line in b shows the sec-tional plane of a. The limen nasi islocated at the junction of the pinkand red areas.b Medial nasal wall. 1, Bony nasalbridge; 2, nasal septum;3, upper lateral nasal cartilage;4, nasal cavity; 5, alar cartilage;6, nasal vestibule; 7, nasal ala;8, nasal columella with medialcrus of the cartilaginous ala;9, filaments of the olfactorynerve; 10, olfactory bulb;11, palatine bone; 12, perpendic-ular plate of the ethmoid;13, vomer; 14, pharyngeal eusta-chian tube ostium.

aus: Behrbohm u. a., Ear, Nose, and Throat Diseases (ISBN 9783136712030) © 2009 Georg Thieme Verlag KG

The internal nasal valve or limen nasi is a veryimportant structure from the physiologic point ofview. It lies at the junction of the vestibule and thenasal cavity. It is formed by a prominence of theanterior edge of the upper lateral or triangular car-tilage on the lateral wall of the nose (Fig. 2.3a). Theinternal nasal valve is normally the narrowest pointin the entire cross-section of the nasal cavity, mak-ing it an important factor in nasal respiration (see p.135).

The nasal cavity extends from the internal nasalvalve to the choana. The structure of the floor androof of the nose, the medial wall, and the nasalseptum is shown in Fig. 2.3a, b.

The outline of the lateral wall of the nasal cavityis more complex than that of the medial wall. Itcontains several structures that are important inthe functioning of the nose and nasal cavity (Fig.2.4):● Three nasal turbinates (superior, middle, and

inferior)● Drainage of the paranasal sinuses (frontal sinus

and maxillary sinus through the hiatus semilu-naris in the middle meatus, located between theinferior and middle turbinate; the sphenoid si-nus has an ostium of its own in the sphenoeth-moidal recess)

● Opening of the nasolacrimal duct into the infe-rior meatus

The superior, middle, and inferior meatus are lo-cated inferior to the three turbinates (Fig. 2.4); theparanasal sinuses and the nasolacrimal duct openinto them. These openings are of diagnostic andtherapeutic importance.● The inferiormeatus, located between the floor of

thenose and the insertion of the lower turbinate,lacks a sinus ostium, but contains the opening ofthe nasolacrimal duct ≈ 3 cm posterior to theexternal nasal opening and 3 mm posterior tothe head of the inferior turbinate (Fig. 2.4).

● The middle meatus, between the inferior andmiddle turbinate, is of clinical importance be-cause the frontal recess, the anterior ethmoidcells, and the maxillary antrum open into it(Fig. 2.4).

● The superior meatus, between the middle andsuperior turbinate, contains the opening for theposterior ethmoid cells. The sphenoid ostium islocated on the anterior wall of the sphenoid si-nus, at the level of the superior meatus (Fig. 2.4).

118 2 Nose, Nasal Sinuses, and Face

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Fig. 2.4 Lateral nasal wall. I,Superior meatus; II, middlemeatus; III, inferior meatus.1, Nasal vestibule; 2, opening ofthe nasolacrimal duct; 3, originof the inferior turbinate;4, semilunar hiatus; 5, insertionof the middle turbinate;6, sphenoid sinus; 7, insertion ofthe superior turbinate; 8, frontalsinus. a, Drainage of the antralcavity; b, drainage of the frontalsinus; c, drainage of the anteriorethmoid cells; d, drainage of theposterior ethmoid cells;e, drainage of the sphenoidsinus; f, area of infundibulum(dotted area).

aus: Behrbohm u. a., Ear, Nose, and Throat Diseases (ISBN 9783136712030) © 2009 Georg Thieme Verlag KG

The nasal cavity is lined by two types of epithelium: respira-tory and olfactory (Figs. 2.5a–d, 2.6a, b). Respiratory epithe-lium coats the entire airway and its projections and exten-sions (e. g., the paranasal sinuses and the middle ear), fromthe nasal introitus to the bronchi. It shows morphologicvariation in different parts of the respiratory tract. Figure2.5c, d shows the structure of the respiratory epithelium of

the nasal cavity. The epithelium is columnar-ciliated withgoblet cells and a layer of mixed glands, a fairly well demar-cated lymphoid cell zone and well developed venous caver-nous spaces in the turbinates and around the ostia (Fig.2.5a).

The olfactory mucosa, innervated by fibers of the olfac-tory nerve, covers the area of the olfactory cleft, the cribri-

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Fig. 2.5a–d a Frontal sectionthrough the nasal cavity. Thenasal mucosa is constricted onthe left side and normal on theright.b Respiratory mucosa. 1, Middleturbinate; 2, antrum with os-tium; 3, nasal septum; 4, inferiorturbinate; 5, layer of mucus;6, respiratory epithelium withcilia; 7, goblet cells; 8, mucosalglands.c Sagittal section through thenose with the septum reflectedsuperiorly. 1, Olfactory region;2, middle turbinate; 3, inferiorturbinate.d 1, Scent molecules dock ontoreceptors; 2, bipolar nerve cells;3, olfactory bulb with 4, glo-merulus (microcenter) and5, mitral cells.

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Fig. 2.6a, b a 1, Scent mole-cules, 2, scent receptors. Eacholfactory cell bears only a singletype of receptor. There are 350types of receptor in humans. Areceptor can recognize up to100 structurally similar mole-cules in a scent category.b Scent molecules only fit onespecific receptor. They trigger abiochemical reaction and a sub-sequent electrical signal, whichis transmitted to the olfactorycenter in the brain.

aus: Behrbohm u. a., Ear, Nose, and Throat Diseases (ISBN 9783136712030) © 2009 Georg Thieme Verlag KG

form plate, part of the superior turbinate, and the part of theseptum lying opposite it. The structure is shown in Fig. 2.5 d,and its topographic extent in Fig. 2.5c. Bowman glandsoccur specifically in this area. They produce a lipo-lipid se-cretion that covers the olfactory region and aids in olfactoryperception due to the enzymes it contains. It is entirelydissimilar to the secretion of the glands of the respiratoryepithelium.

■ Paranasal Sinuses

The paranasal sinuses are pneumatized cavities inthe bone adjacent to the nose (Fig. 2.7a, b).

Ostiomeatal ComplexThe ostiomeatal complex is a functional entity inthe anterior ethmoid complex that represents thefinal common pathway for drainage and ventilationof the frontal, maxillary, and anterior ethmoid cells(see Fig. 2.9). Anyor all cells, clefts, and ostia, aswell

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Fig. 2.7a, b The paranasal si-nuses.a Arrangement of the paranasalsinuses in the facial skeleton.b The mucosal surface of theparanasal sinuses is substantiallylarger than that of the nose. Thearrows indicate the mucociliarytransportation of secretions outof the sinuses to the nose.a, Frontal sinus; b, ethmoid cellsystem; c, maxillary sinus;d, sphenoid sinus.

Fig. 2.8 Anatomy of the ethmoid bone. 1, Labyrinth;2, perpendicular lamina; 3, ethmoidal bulla; 4, crista galli.

as their dependent sinuses, can become diseased,contributing to the symptoms and pathophysiologyof sinusitis.

Ethmoidal LabyrinthThe central structure in this system of pneumatizedcavities is the ethmoid bone. The anterior ethmoid isthe morphologic connection and secretion channelbetween the nose and the frontal and maxillarysinuses. The tight spaces and clefts normally ensureventilation and drainage of the sinus mucosa. Theanterior ethmoid is central to the pathogenesis ofacute, recurrent, and chronic inflammations of thefrontal and maxillary sinuses, since ≈ 90% of alldiseases of the frontal and maxillary sinuses beginhere.

The central part of the ethmoid bone is T-shaped.In the median plane, the crista galli projects into theanterior fossa (Fig. 2.8). The falx cerebri inserts here.The perpendicular plate (lamina perpendicularis)abuts anteriorly onto the septal cartilage and dor-sally onto the vomer. The paired ethmoidal labyrinthis situated between the nose and orbit. It consists of10 to 15 pneumatized cells lined with respiratoryepithelium. The volumevaries individually; roughly,it is the size of amatchbox standing on its short side.

The lamina cribrosa passes into the ethmoidalnotch (incisura ethmoidalis) of the frontal bone.The olfactory nerves extend from the olfactory rimto the olfactory bulb.

The ethmoid air cells are differentiated into anterior andposterior groups. They are derived from an embryonicpaired anlage that coalesces in the first year of life to forma single ethmoid cell. There are communications between allof the ethmoid cells on one side. There are often alsocommon ostia for the anterior ethmoid complex in the

aus: Behrbohm u. a., Ear, Nose, and Throat Diseases (ISBN 9783136712030) © 2009 Georg Thieme Verlag KG