venous territories of the face. The frontomedian region of the face, and behind (see Fig. 33.3D and E). The anterior slope is formed by the
including the nose, drains to the facial vein, and the orbitopalpebral nasal spine of the frontal bones and by the nasal bones. The central
area of the face, including the root of the nose, drains to the ophthalmic region is formed by the cribriform plate of the ethmoid bone, which
veins. The connections of the veins of the nose, upper lip and cheek separates the nasal cavity from the floor of the anterior cranial fossa. It
(the ‘danger triangle of the face’) with the drainage area of the valveless contains numerous small perforations that transmit the olfactory nerves
ophthalmic veins, and hence to the cavernous sinus, are clinically sig- and their ensheathing meningeal layers, and a separate anterior foramen
nificant because they can be a route for spreading infection that initiates that transmits the anterior ethmoidal nerve and vessels. The height of
thrombosis of the major intracranial sinuses. Lymph drainage is pri- the cranial base is greatest anteriorly; hence, when dissecting along the
marily to the submandibular group of nodes, although lymph draining cranial base during sinus surgery, it is safest to do so from back to front,
from the root of the nose drains to superficial parotid nodes. addressing the lower-lying posterior region first to avoid inadvertent


Nose, nasal cavity and paranasal sinuses
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Although each muscle is independent in terms of innervation and func-
tion, the mimetic muscles of the nose form a continuous layer with
connections between all the muscular and ligamentous components
(Saban et al 2008). Thus, the superficial muscular aponeurotic system
is continuous from the nasofrontal process to the nasal tip, splitting at
the caudal end of the lateral cartilage into superficial and deep layers,
each with medial and lateral components (Oneal et al 1999). Dissec-
tion in rhinoplasty is usually performed in a sub-superficial muscular
aponeurotic system plane. (For further information on the superficial
muscular aponeurotic system, see p. 476.)


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intracranial penetration. Posteriorly, the roof of the nasal cavity is Arrow in orifice of sphenoidal sinus,
formed by the anterior aspect of the body of the sphenoid, interrupted passing into sphenoethmoidal recess
on each side by an opening of a sphenoidal sinus, and the sphenoidal Orifice of posterior group
conchae or superior conchae. of ethmoidal air cells
Orifices of bullar sinuses opening
FLOOR into bulla ethmoidalis
The floor of the nasal cavity is smooth and concave transversely, and Hiatus semilunaris
slopes up from the anterior to the posterior apertures. The greater part
is formed by the palatine processes of the maxillae, which articulate
posteriorly with the horizontal plates of the palatine bones at the pal- Left frontal sinus
atomaxillary suture (see Figs 33.3D, E). Anteriorly, near the septum, a
small infundibular opening in the bone of the nasal floor leads into
the incisive canals that descend to the incisive fossa; this opening is
marked by a slight depression in the overlying mucosa.
The floor of the nose may be deficient as a result of congenital clef-
ting of the hard and/or soft palate.
MEDIAL WALL
The medial wall of each nasal cavity is the nasal septum, a thin sheet
of bone (posteriorly) and cartilage (anteriorly) that lies between the
roof and floor of the cavity (see Figs 30.4, 33.3D).
Bony septum
Opening of
The septum is usually relatively featureless but sometimes exhibits pharyngotympanic tube
ridges or bony spurs. The posterosuperior part of the septum and its Orifice of maxillary sinus
posterior border are formed by the vomer, which extends from the body
of the sphenoid to the nasal crest of the palatine bones and maxilla Orifices of frontonasal ducts
or ethmoidal infundibulum Orifice of nasolacrimal duct
(see Fig. 30.4). The nasopalatine nerves and vessels groove its surface.


(The nasopalatine artery, also known as the septal artery, is a branch of Fig. 33.6 The lateral wall of the nasal cavity. The conchae have been
the maxillary artery; it leaves the pterygop alatine fossa through a canal removed to show the positions of the ostia of the paranasal sinuses and
inside the palatine bone, runs parallel to the nasopalatine nerve and the nasolacrimal duct. (From Drake RL, Vogl AW, Mitchell A (eds), Gray’s
ends in the incisive canal, where it anastomoses with the greater pala- Anatomy for Students, 2nd ed, Elsevier, Churchill Livingstone. Copyright
tine artery.) The anterosuperior part of the septum is formed by the 2010.)
perpendicular plate of the ethmoid, which is continuous above with
the cribriform plate and the frontal bone. Other bones that make minor
contributions to the septum at the upper and lower limits of the medial the medial wall of the maxilla that are obliterated to varying degrees by
wall are the nasal bones and the nasal spine of the frontal bones fibrous tissue); posteriorly by the perpendicular plate of the palatine
(anterosuperior), the rostrum and crest of the sphenoid (posterosupe- bone; and superiorly by the labyrinth of the ethmoid bone (Fig. 33.6;
rior), and the nasal crests of the maxilla and palatine bones see Figs 33.3E, 30.5). It contains three projections of variable size: the
(inferior). inferior, middle and superior nasal conchae or turbinates.
The conchae curve inferomedially in general, each roofing a groove,
Cartilaginous septum or meatus, which is open to the nasal cavity. The middle concha may
also curve inferolaterally; less commonly, it may sometimes be expanded
by an enclosed air cell to form a so-called ‘concha bullosa’, or occasion-
The septal cartilage is almost quadrilateral and may extend back (espe-
ally may have a concave medial surface, known as a paradoxical tur-
cially in children) for some distance between the vomer and the per-
binate. The main features of the lateral nasal wall are a rounded


pendicular plate of the ethmoid. Its anterosuperior margin is connected
elevation, the bulla ethmoidalis, and a curved cleft, the hiatus semilu-
above to the posterior border of the internasal suture, and the distal
naris, formed by the posterior edge of the uncinate process and the
end of its superior portion is continuous with the upper lateral carti-
anterior face of the ethmoidal bulla. This constitutes the medial limit
lages. The anteroinferior border is connected by fibrous tissue on each
of the ethmoidal infundibulum, a slit-like space that leads towards the
side to the medial crurae of the major alar cartilage. Anteroinferiorly,
maxillary ostium. The maxillary ostium is normally found lateral to the
the cartilaginous septum is attached to the anterior nasal spine, which
anteroinferior aspect of the uncinate process. The latter may be attached
is formed by anterior projections of each maxillary crest, and it has a
to either the lateral nasal wall (50%), or the anterior cranial fossa (25%)
strong, tongue-in-groove attachment with the premaxilla and vomer.
or the middle concha (25%). Where the uncinate process is attached
The cartilaginous septum anterior to the spine is essential in tip support
determines whether the frontal sinus drains lateral to the ethmoidal
and should not be excised during septal surgery in order to prevent
infundibulum or into it. If the uncinate process is attached to the lateral
columellar retraction or loss of tip support. The posterosuperior border
wall, the frontal sinus will drain into the middle meatus and not into
joins the perpendicular plate of the ethmoid, while the posteroinferior
the ethmoidal infundibulum, whereas with the other configurations,
border is attached to the vomer and, anterior to that, to the nasal crest
the sinus will drain into the infundibulum, and thus near or into the
and anterior nasal spine of the maxilla. The anteroinferior part of the
maxillary ostium. Agger nasi air cells are anterior ethmoidal air cells
nasal septum between the nares is devoid of cartilage and is therefore


that lie anterior to the ethmoidal bulla (see Fig. 33.6). The posterior
called the membranous septum; it is continuous with the columella
fontanelle lies posterior to the uncinate process where there is no bone
anteriorly.
in the medial wall of the maxillary sinus, inferoposterior to the hiatus,
Above the incisive canals, at the lower edge of the septal cartilage, a
and frequently has an accessory opening (Fig. 33.7).
depression pointing downwards and forwards is all that remains of the
nasopalatine canal, which connected the nasal and buccal cavities in
Inferior concha and inferior meatus
early fetal life. Near this recess, a minute orifice leads back into a blind
tubule, 2–6 mm long, which lies on each side of the septum and houses
remnants of the vomeronasal organ (see below). The inferior concha is a thin, curved, independent bone (for more
details, see p. 483). It articulates with the nasal surface of the maxilla
and the perpendicular plate of the palatine bone. Its free lower border
LATERAL WALL is gently curved and the subjacent inferior meatus reaches the nasal
floor. The inferior meatus is the largest meatus, extending along almost
The lateral wall of the nasal cavity is formed anteroinferiorly by the all the lateral nasal wall. It is deepest at the junction of its anterior and
maxilla and its anterior and posterior fontanelles (bony deficiencies in middle thirds, where it admits the inferior opening of the nasolacrimal


Nose, nasal cavity and paranasal sinuses
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RETPAHC
Septum MT Inferior turbinate Ethmoid bulla Hiatus semilunaris MT
A B C
MT Uncinate Ostium
process
Posterior wall
of nasopharynx
Orifice of
Vomer
Pharyngotympanic
(Eustachian) tube
D E
Fig. 33.7 A, An endoscopic view of the nasal cavity showing inferior and middle turbinates (MT). B, A view of the middle meatus and left lateral wall of
the nose. C, An endoscopic view of the nose showing the middle turbinate and the pneumatized uncinate process in the middle meatus (asterisk). D, An
endoscopic view of the nose demonstrating a deviated nasal septum (asterisk) making contact with the left inferior turbinate. E, An endoscopic view of
the posterior nasal space.


Nasal cavity
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33
RETPAHC
canal. The canal is formed by the articulations between the lacrimal erectile tissue, linked to trigeminal innervation detecting airflow and
groove of the maxilla, the descending process of the lacrimal bone and temperature; congestion and decongestion of the venous sinusoids
the lacrimal process of the inferior concha. During postnatal develop- regulate nasal resistance. Turbinates are also essential for filtration,
ment, the ostium of the nasolacrimal duct moves upwards and is heating and humidification of inspired air. They direct airflow to the
increasingly hidden under the over-arching inferior concha. Inconsist- olfactory cleft, and some areas receive direct innervation from the olfac-
ent epithelial folds (the valve of Hasner) may remain at its distal tory bulb. Hypertrophy of the turbinates in allergy or environmental
opening. irritation results in nasal obstruction.
Middle concha and middle meatus
NASAL AIRFLOW AND THE NASAL CYCLE
The middle concha is a medial process of the ethmoidal labyrinth and
may be pneumatized (conchal sinus). It extends back to articulate with Available with the Gray’s Anatomy e-book
the perpendicular plate of the palatine bone. The region beneath it is
the middle meatus, which is deeper in front than behind, lies below
Nasal obstruction
and lateral to the middle concha, and continues anteriorly into a
shallow fossa above the vestibule, termed the atrium of the middle
meatus. Disturbances of the normal airflow pattern, whether produced by
mucocutaneous or skeletal changes within the nose, affect normal
Sphenopalatine foramen
nasal breathing and are usually perceived as some form of nasal
The sphenopalatine foramen, which is really a fissure, transmits the obstruction.
sphenopalatine artery and nasopalatine and superior nasal nerves from The septum may be displaced by injury or by disproportionate
the pterygopalatine fossa. It is posterior to the middle meatus, and growth of the cartilage that may cause it to bend; sometimes, the devi-
bounded above by the body and concha of the sphenoid, below by the ation may cause unilateral nasal obstruction. Variations in the anatomy


superior border of the perpendicular plate of the palatine bone, and in of the lateral nasal wall, usually associated with variations in the size
front and behind by the orbital and sphenoidal processes of the pala- and position of the anterior ethmoidal cells, may obstruct frontal or
tine bone, respectively. The crista ethmoidalis, a small bony crest formed maxillary sinus drainage, e.g. frontal cells, supraorbital ethmoidal cells,
by the attachment of the basal lamella of the middle turbinate to the and infraorbital or Haller’s cells, which represent an extension of an-
ascending palatine bone, is found anterior to the foramen, and is a terior ethmoidal pneumatization along the infraorbital margin, some-
reliable surgical landmark. times within the roof of the maxillary sinus (see below).
Ethmoturbinals
The ethmoturbinals are the superior and middle turbinates, occasion- NASAL AND OLFACTORY MUCOSAE
ally supplemented by a supreme turbinate. They appear during weeks
nine and ten of gestation as multiple folds on the developing lateral Nasal mucosa
nasal wall and subsequently fuse into three or four ridges, each with an
anterior (ascending) and a posterior (descending) ramus, separated by
The lining of the anterior part of the nasal cavity and vestibule is con-
grooves. The first ridge develops into the agger nasi and the uncinate
tinuous with the skin, and consists of keratinized stratified squamous
process. The second is thought to become the ethmoidal bulla and the
epithelium overlying a connective tissue lamina propria. Inferiorly, the
fourth, if present, develops into the superior and supreme turbinates.
skin bears coarse hairs (vibrissae), which curve towards the naris and
The third is known as the basal lamella of the middle turbinate.
help to arrest the passage of particles in inspired air. In males, after
Attachments of the basal lamella of middle age, these hairs increase considerably in size. Further posteriorly,
the middle turbinate at the limen nasi, this changes into a mucosa, lined initially by non-
keratinizing stratified squamous epithelium, and then by pseudostrati-
An understanding of the attachment of the middle turbinate to the roof


fied ciliated (respiratory) epithelium rich in goblet cells (see Fig. 2.2D).
and lateral wall of the nose is essential when undertaking sinus surgery.
Respiratory epithelium forms most of the surface of the nasal cavity, i.e.
Anteriorly, it attaches to the crista ethmoidalis of the maxilla, and pos-
it covers the conchae, meatuses, septum, floor and roof, except superi-
teriorly it attaches to the crista ethmoidalis of the palatine bone, an-
orly in the olfactory cleft, where the olfactory epithelium is present. It
terior to the sphenopalatine foramen. In between these points, the
is adherent to the periosteum or perichondrium of the neighbouring
insertion lies in three different planes. The anterior third inserts verti-
skeletal structures. In some areas, cells of the respiratory epithelium
cally into the cranial base. The middle third turns laterally across the
may be low columnar or cuboidal, and the proportion of ciliated to
cranial base to the lamina papyracea, where it turns inferiorly; it may
non-ciliated cells is variable.
be indented by either anterior or posterior ethmoidal cells, but sepa-
There are numerous seromucous glands within the lamina propria
rates the two groups of cells. The posterior third runs horizontally,
of the nasal mucosa. Their secretions make the surface sticky so that it
attaching to the lamina and the medial wall of the middle turbinate.
traps particles in the inspired air. The mucous film is continually moved
by ciliary action (the mucociliary escalator or rejection current) poster-
Superior concha and superior meatus
iorly into the nasopharynx at a rate of 6 mm per minute. Palatal move-
ments transfer the mucus and its entrapped particles to the oropharynx
The superior concha is a medial process of the ethmoidal labyrinth and for swallowing, but some also enters the nasal vestibule anteriorly. The
presents as a small curved lamina, posterosuperior to the middle secretions of the nasal mucosa contain the bacteriocides lysozyme,


concha. It roofs the superior meatus and is the shortest and shallowest β-defensin and lactoferrin, and also secretory immunoglobulins (IgA).
of the three conchae. Above the superior concha, the sphenoidal sinus The mucosa is continuous with the nasopharyngeal mucosa through
opens into the triangular sphenoethmoidal recess, which separates the the posterior nasal apertures, the conjunctiva through the nasolacrimal
superior concha and anterior aspect of the body of the sphenoid. The duct and lacrimal canaliculi, and the mucosa of the sphenoidal,
superior meatus is a short oblique passage extending about halfway ethmoidal, frontal and maxillary sinuses through their openings into
along the upper border of the middle concha. The posterior ethmoidal the meatuses.
sinuses open, via a variable number of apertures, into its anterior part. The mucosa is thickest and most vascular over the conchae, espe-
cially at their extremities, and also on the anterior and posterior parts
Highest (supreme) nasal concha of the nasal septum and between the conchae. The mucosa is very thin
in the meatuses, on the nasal floor and in the paranasal sinuses. Its
Occasionally, a fourth concha, the highest or supreme nasal concha, thickness reduces the volume of the nasal cavity and its apertures sig-
appears on the lateral wall of the sphenoethmoidal recess. The passage nificantly. The lamina propria contains cavernous vascular tissue with
immediately below it is called the supreme nasal meatus; it may contain large venous sinusoids.
an opening for the posterior ethmoidal sinus.
Olfactory mucosa
Functions of the nasal turbinates
Olfactory mucosa (Fig. 33.8) covers approximately 5 cm2 of the pos-
In vivo, the conchae are covered with a thick, vascular, glandular soft terior upper parts of the lateral nasal wall, including the upper part of
tissue layer with pseudostratified columnar epithelium. They contain the vertical portion of the middle concha (where it is interspersed with


Nose, nasal cavity and paranasal sinuses
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RETPAHC
The paired nasal valves are critical regulators of nasal airflow and resist- and Eccles 2006). It is generally agreed that airflow within the nose is
ance. Each is divided into external and internal portions, although often both laminar and turbulent. Inspired air is forced to pass through the
only the internal portion is regarded as the ‘nasal valve’ or flow-limiting nasal valve and then expands as it passes further into the nasal cavity,
segment. The external valve is made up of the ala, the skin of the ves- which offers little airflow resistance. This sudden change in speed and
tibule, the nasal sill and the contour of the medial crus of the lower pressure produces turbulence and eddies. These currents allow adequate
lateral cartilage. The external valve has a tendency to collapse at high contact of inspired air with respiratory epithelium and facilitate odorant
flow rates, even in normal individuals. transport to the olfactory area. Chewing also affects nasal airflow; pulses
The upper lateral cartilages are in continuity with the superior border of aroma-laden air are pumped out of the mouth into the retronasal
of the nasal septum. A valve-like mechanism exists at its distal end that region with each chew.
regulates nasal airflow. The nasal valve area and internal nasal valve are The cross-sectional area of the nasal airway depends on the dimen-
two entities that should not be confused. The nasal valve area is the sions of the septal partition and inferior turbinates (which are modu-
narrowest portion of the nasal passage. It is bounded medially by the lated by changes in the dimensions of the erectile tissue that covers
septum and the tuberculum of Zuckerkandl, and superiorly and later- them), and on the stability of the lateral nasal walls during breathing.
ally by the caudal margin of the upper lateral cartilage, its fibroadipose The nasal cycle is an alternating fluctuation of nasal engorgement and
attachment to the piriform aperture and the anterior end of the inferior airflow through the nasal passages, with period lengths ranging from 1
turbinate; inferiorly, it consists of the floor of the piriform aperture. The to 5 hours. The mechanism involves changes in sympathetic tone to


nasal valve, on the other hand, is the specific slit-like segment between the venous erectile tissue of the nasal mucosa; increased sympathetic
the caudal margin of the upper lateral cartilage and the septum. It is vasoconstriction causes resistance to fall. These alterations in the thick-
measured in degrees and normally ranges between 10 and 15°. Dilator ness and contours of the mucosal surfaces are visible as a swelling or
naris anterior and the alar part of nasalis support the nasal valves. shrinkage of the nasal lining, and may serve to protect the mucosae
Airflow dynamics are recognized as playing a key role in condition- from desiccation. The pacemaker for the cycle is believed to lie within
ing (i.e. warming, humidifying and filtering) inspired air; however, the suprachiasmatic nucleus. The rhythmicity of the cycle decreases
these dynamics are still poorly understood (Churchill et al 2004, Boyce with age.
V
C
B
M
S
S
S
C D
Fig. 33.8 C, A higher-power view of the expanded end of an olfactory receptor neurone. The electron-dense, osmiophilic material within the adjacent
supporting cell (S) is thought to contribute to the pigmentation of the olfactory epithelium. Other abbreviations: B, basal body with projecting
‘feet’; C, olfactory cilium; M, microtubules. D, A section of human olfactory epithelium immunostained with anti-OMP (olfactory marker protein).
An immunopositive olfactory receptor neurone lies between two unstained supporting cells (S). Other abbreviations: V, microvilli.


NosE, NAsAL CAviTy ANd PARANAsAL siNusEs
562
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NoiTCEs
N
S
M
I
S S
R
B
G
B
G
S B
A B BG
Fig. 33.8 A, The chief cytological features of the olfactory epithelium. Receptor cells (neurones) (R) are situated among columnar sustentacular cells. The
axons of the receptor cells emerge from the epithelium in bundles enclosed by ensheathing glial cells (G). Rounded globose basal cells (B) and flattened
horizontal basal cells (not shown) lie on the basal lamina, and the subepithelial glands (of Bowman) (S) open on to the surface via their intraepithelial
ducts (I). At the surface are cilia of the receptor cells and microvilli of the supporting cells. B–D, Longitudinal sections through human olfactory
epithelium. B, Ciliated olfactory receptor neurones with characteristic expanded ends (N) project into the nasal lumen. The edge of a Bowman’s gland
(BG) lies deeper in the lamina propria. Other abbreviations: B, basal cells resting on the basal lamina; M, microvillar cell; S, supporting or sustentacular
cells containing electron-dense material. (B–D, Courtesy of Professor Bruce Jafek, Department of Otolaryngology, University of Colorado, Denver, USA.)
respiratory epithelium in a chequerboard fashion) and the opposite the same glomerulus in the olfactory bulb. Specific odours activate a
part of the nasal septum, the superior concha, the sphenoethmoidal unique spectrum of receptor neurones, which in turn activate restricted
recess, the upper part of the perpendicular plate of the ethmoid and the groups of glomeruli and their second-order neurones.
portion of the roof of the nose that arches between the septum and The axons form small intraepithelial fascicles among the processes
lateral wall, including the underside of the cribriform plate (constitut- of sustentacular and basal cells. The fascicles penetrate the basal lamina
ing the olfactory cleft or groove). It consists of a yellowish-brown and are immediately surrounded by olfactory ensheathing cells. Groups


pigmented pseudostratified epithelium, containing olfactory receptor of up to 50 such fascicles join to form larger olfactory nerve rootlets
neurones, sustentacular cells and two classes of basal cell, lying on a that pass through the cribriform plate of the ethmoid bone, wrapped
subepithelial lamina propria containing subepithelial olfactory glands in meningeal sheaths. They immediately enter the overlying olfactory
(of Bowman) and bundles of axons derived from the olfactory receptor bulbs, where they synapse in glomeruli with mitral cells and, to a lesser
neurones that course through the mucosa on their way to the cribriform extent, with smaller tufted cells.
plate. The glands secrete a predominantly serous fluid through ducts
that open on to the epithelial surface. These secretions form a thin fluid Microvillar cells Microvillar cells occupy a superficial position in the
layer in which sensory cilia and the microvilli of the sustentacular cells olfactory epithelium. They are flask-shaped and electron-lucent, and the
are embedded. apical end of each cell gives rise to a tuft of microvilli that project into
the mucus layer lining the nasal cavity (see Fig. 33.8B). Cell counts in
Olfactory receptor neurones Olfactory receptor neurones are longitudinal sections reveal that microvillar cells occur with a density
bipolar. Their cell bodies and nuclei are located in the middle zone of that is approximately one-tenth of the density of ciliated olfactory
the olfactory epithelium. Each neurone has a single unbranched apical neurones; their function and origin have yet to be determined.
dendrite, 2 µm in diameter, which extends to the epithelial surface; and
a basally directed unmyelinated axon, 0.2 µm in diameter, which passes Sustentacular cells Sustentacular, or supporting, cells are columnar
in the opposite direction, penetrates the basal lamina and enters the cells that separate and partially ensheathe the olfactory receptor neur-
lamina propria. The tips of the dendrites project into the overlying ones. Their large nuclei form a layer superficial to the neuronal nuclei
secretory fluid and are expanded into characteristic endings (knobs) within the epithelium. The cells are capped by numerous long, irregular,


(see Fig. 33.8B). Groups of up to 20 cilia radiate from the circumference microvilli, which lie in the secretory fluid layer that covers the surface
of each ending and extend for long distances parallel to the epithelial of the epithelium, intermingled with the trailing ends of the cilia on
surface. Internally, the short proximal part of each cilium has the ‘9 + 2’ the olfactory receptor endings. Their expanded bases contain numerous
pattern of microtubules typical of motile cilia, while the longer distal lamellated dense bodies, which are the remnants of secondary lyso-
trailing end contains only the central pair of microtubules. The olfac- somes, and which contribute significantly to the pigmentation of the
tory cilia lack dynein arms and are thought to be non-motile; their olfactory area (see Fig. 33.8B,C). The granules gradually accumulate
primary purpose is to increase the surface area of sensory receptor with age, and because these cells are long-lived, the intensity of pigmen-
membrane available for the efficient detection of odorant molecules tation also increases with age. Neighbouring sustentacular cells are
transferred across the mucous layer by odorant-binding proteins. linked by desmosomes close to the epithelial surface, an arrangement
Mature olfactory neurones express olfactory marker protein (OMP), an that helps to stabilize the epithelium mechanically. Sustentacular cells
abundant cytoplasmic protein involved in olfactory signal transduction and olfactory receptor neurones are linked by tight junctions at the level
(see Fig. 33.8D). Each olfactory receptor neurone expresses receptors of the epithelial surface.
for a single odorant molecule (or very few). In humans, over 1000 genes
code for functional odorant receptors; the number of functional genes Basal cells There are horizontal and globose basal cells. Horizontal
is much higher in macrosmotic animals (Buck and Axel 1991). Although basal cells are flattened against the basal lamina. Their nuclei are con-
neurones with the same receptor specificity are randomly distributed densed and their darkly staining cytoplasm contains numerous inter-
within anatomical zones of the epithelium, their axons all converge on mediate filaments of the cytokeratin family, inserted into desmosomes


Nasal cavity
563
33
RETPAHC
between the basal cells and surrounding sustentacular cells. Globose VASCULAR SUPPLY AND LYMPHATIC DRAINAGE OF
cells are rounded or elliptical in shape, and have pale, euchromatic THE NASAL CAVITY
nuclei and pale cytoplasm. They form a distinct zone that is slightly
internal to the basal surface of the epithelium and characterized by
Many of the vessels and nerves supplying the nasal cavities arise within
mitotic figures; globose basal cells are the immediate source of new
the pterygopalatine fossa and these origins are described in Chapter 32.
olfactory receptor neurones.
Arteries
Olfactory ensheathing cells Olfactory ensheathing cells share
properties with astrocytes and non-myelinating Schwann cells, but also
possess distinctive features that indicate they are a separate class of glia. Branches of the ophthalmic, maxillary and facial arteries supply differ-
Developmentally, they are derived from the olfactory placode rather ent territories within the walls, floor and roof of the nasal cavity (Fig.
than the neural crest. They ensheathe olfactory axons in a unique 33.9). They ramify to form anastomotic plexuses within and deep to
manner throughout their entire course and accompany them into the the nasal mucosa. Anastomoses also occur between some larger arterial
olfactory bulb, where they contribute to the glia limitans. In recent branches. The anterior and posterior ethmoidal branches of the oph-
years, olfactory ensheathing cells have been the focus of intense experi- thalmic artery supply the ethmoidal and frontal sinuses and the roof
mental scrutiny in the search for a source of transplantable glia capable of the nose (including the septum). The anterior ethmoidal artery
of supporting neuronal regeneration within the central nervous system, usually runs within the bone of the anterior skull base, unless this is
possibly in the treatment of paraplegia. well pneumatized with a supraorbital cell, in which case the artery is
more likely to be positioned away from the skull base and to be more
Olfactory glands Olfactory (Bowman’s) glands are branched tubulo- prone to surgical damage. The sphenopalatine branch of the maxillary


alveolar structures that lie beneath the olfactory epithelium and secrete artery supplies the mucosa of the turbinates, meatuses and posteroin-
their products on to the epithelial surface through narrow, vertical ferior part of the nasal septum, i.e. it is the principal vessel supplying
ducts. Their secretions, which include defensive substances, lysozyme, the nasal mucosa. The artery comes out of a fissure (erroneously termed
lactoferrin, IgA and sulphated proteoglycans, together with odorant- a foramen), and normally divides before it enters the nasal cavity
binding proteins which increase the efficiency of odour detection, bathe behind the crista ethmoidalis into posterior lateral nasal and posterior
the dendritic endings and cilia of the olfactory receptors. The fluid acts septal branches. Sometimes, the artery may divide before it leaves the
as a solvent for odorant molecules, allowing their diffusion to the foramen. The number and distribution of its branches show great vari-
sensory receptors. ation, with a median of three or four branches (Babin et al 2003). The
greater palatine branch of the maxillary artery supplies the region of
Turnover of olfactory receptor neurones Olfactory receptor the inferior meatus. A branch crosses the sphenoidal rostrum, below its
neurones are lost and replaced throughout life. Individual receptor cells natural ostium, to supply the nasal septum. This is utilized to provide
have a variable lifespan, thought to average 1–3 months. Stem cells situ- pedicled, vascularized nasoseptal flaps in skull-base reconstruction. Its
ated near the base of the epithelium undergo periodic mitotic division terminal part ascends through the incisive canal to anastomose on the
throughout life, giving rise to new olfactory receptor neurones, which septum with branches of the sphenopalatine and anterior ethmoidal
then grow a dendrite to the olfactory surface and an axon to the olfac- arteries, and with the septal branch of the superior labial artery. This
tory bulb. The cell bodies of these new receptor neurones gradually septal region (Little’s area or Kiesselbach’s plexus) is a common site of


move apically until they reach the region just below the supporting cell bleeding from the nose. The infraorbital artery and the superior, ante-
nuclei. When they degenerate, dead neurones either are shed from the rior and posterior alveolar branches of the maxillary artery supply the
epithelium or are phagocytosed by sustentacular cells. The rate of recep- mucosa of the maxillary sinus. The pharyngeal branch of the maxillary
tor cell loss and replacement increases after exposure to damaging artery supplies the sphenoidal sinus.
stimuli but declines slowly with age, a phenomenon that presumably
contributes to diminishing olfactory sensory function in old age. Biopsy Nose bleeds
specimens from normosmic adults have revealed that patchy replace-
ment of olfactory with respiratory epithelium occurs even in young
Available with the Gray’s Anatomy e-book
healthy adults (Paik et al 1992, Holbrook et al 2005).
A B
Anterior ethmoidal artery Septal branch of
anterior ethmoidal artery
Middle concha
Septal branch of
posterior ethmoidal artery
Posterior ethmoidal artery
Superior concha External nasal branch
of anterior ethmoidal artery
Septal branch of
sphenopalatine
artery
Alar branch of Septal branch of
Lateral branches of lateral nasal artery nasal artery (from
sphenopalatine artery superior labial artery)
Terminal part of
Inferior concha
greater palatine artery
Fig. 33.9 The arterial supply of the nasal cavity. A, The lateral wall of the left nasal cavity. B, The medial wall of the left nasal cavity. (From Drake RL,
Vogl AW, Mitchell A (eds), Gray’s Anatomy for Students, 2nd ed, Elsevier, Churchill Livingstone. Copyright 2010.)


Nose, nasal cavity and paranasal sinuses
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The vast majority of nose bleeds, particularly in children, occur as a
result of digital trauma to the anastomosis of arterioles and veins in
Little’s area, on the nasal septum just inside the nasal vestibule. This
area is amenable to cautery when required. In older patients, brisker
bleeding may occur as a result of the spontaneous rupture of arteries
further back in the nose. These may be controlled by applying pressure
with a nasal pack, but where this fails, knowledge of the pattern of
arterial blood supply to the nasal cavity permits interruption of the
appropriate blood supply by ligation or embolization of the feeding
vessel. The sphenopalatine artery may be ligated under endoscopic visu-
alization as it enters the nose through the sphenopalatine foramen. The
ethmoidal arteries may be exposed within the orbit and ligated to arrest
bleeding high up in the nasal cavity. The maxillary artery may be
exposed surgically behind the posterior wall of the maxillary sinus and
ligated, or alternatively it may be identified radiologically, using a radi-
opaque dye, so that it may be blocked by embolization (Simmen and
Jones 2010).


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Veins pterygoid venous plexus. The anterior part of the nose is drained mainly
through veins accompanying the anterior ethmoidal arteries, and these
veins subsequently pass into the ophthalmic or facial veins. Injection
A rich submucosal cavernous plexus is especially dense in the posterior
of vasoconstrictive agents or corticosteroids during surgery, particularly
part of the septum and in the middle and inferior turbinates (Fig.
to the inferior turbinates, may permit access to the intracranial and
33.10). Numerous arteriovenous anastomoses are present in the deep
ophthalmic circulations. Blindness has been reported in rare cases fol-
layer of the mucosa and around the mucosal glands. The cavernous
lowing such injections. A few veins pass through the cribriform plate
turbinate plexuses resemble those in erectile tissue; the nasal cavity is
to connect with those on the orbital surface of the frontal lobes of the
susceptible to blockage, should they become engorged. Veins from the
brain. When the foramen caecum is patent, it transmits a vein from the
posterior part of the nose generally pass to the sphenopalatine vein that
nasal cavity to the superior sagittal sinus.
runs back through the sphenopalatine foramen to drain into the
Lymphatic drainage
Lymph vessels from the anterior region of the nasal cavity pass super-
ficially to join those draining the external nasal skin and end in the
submandibular nodes. The rest of the nasal cavity, paranasal sinuses,
nasopharynx and pharyngeal end of the pharyngotympanic tube all
drain to the upper deep cervical nodes, either directly or through the
retropharyngeal nodes. The posterior nasal floor probably drains to the
Drainage to cavernous parotid nodes.
sinus in cranial cavity
INNERVATION OF THE NASAL CAVITY
Nasal vein in
foramen caecum
Olfaction is mediated via the olfactory nerves. General sensation (touch,
pain and temperature) from the nasal mucosa is carried by branches of


the ophthalmic and maxillary divisions of the trigeminal nerves (Fig.
33.11). Trigeminal fibres close to, and within, the epithelial layer are
sensitive to noxious chemicals, e.g. ammonia and sulphur dioxide.
Autonomic fibres innervate mucous glands and control cyclical and
reactive vasomotor activity.
Trigeminal innervation
The anterior ethmoidal branch of the nasociliary nerve leaves the cranial
cavity through a small slit near the crista galli and enters the roof of the
Drainage to pterygoid Drainage to
nasal cavity, where it runs in a groove on the inner surface of the nasal
plexus in facial vein
infratemporal fossa bone, supplying the roof of the nasal cavity. It gives off a lateral internal
branch to supply the anterior part of the lateral wall, and a medial
internal branch to the anterior and upper parts of the septum, before
emerging at the inferior margin of the nasal bone as the external nasal
Fig. 33.10 The venous drainage of the nasal cavity: the lateral wall of the nerve to supply the skin of the external nose to the nasal tip; damage
left nasal cavity. (From Drake RL, Vogl AW, Mitchell A (eds), Gray’s following nasal trauma may result in paraesthesia of the tip. The
Anatomy for Students, 2nd ed, Elsevier, Churchill Livingstone. Copyright infraorbital nerve supplies the nasal vestibule. The anterior superior
2010.) alveolar nerve supplies part of the septum, the floor near the anterior
A B
Anterior ethmoidal nerve Septal branch of
anterior ethmoidal nerve
Olfactory bulb
Olfactory nerve
Olfactory nerve
External nasal branch
Sphenopalatine of anterior ethmoidal nerve
foramen
Posterior superior
lateral nasal nerve
Posterior inferior
Internal nasal branches
lateral nasal nerves
of infraorbital nerve
Nasal branch of anterior
superior alveolar nerve Nasopalatine nerve
Fig. 33.11 The innervation of the nasal cavity. A, The lateral wall of the left nasal cavity. B, The medial wall of the left nasal cavity. (From Drake RL, Vogl


AW, Mitchell A (eds), Gray’s Anatomy for Students, 2nd ed, Elsevier, Churchill Livingstone. Copyright 2010.)


Paranasal sinuses
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RETPAHC
nasal spine and the anterior part of the lateral wall as high as the 2 1
opening of the maxillary sinus; the lateral posterior superior nasal and
the posterior inferior nasal branches of the greater palatine nerve
together supply the posterior three-quarters of the lateral wall, roof and
floor; the medial posterior superior nasal nerves and the nasopalatine
nerve supply the inferior part of the nasal septum; and branches from
the nerve of the pterygoid canal supply the upper and posterior part of
the roof and septum.
Autonomic innervation
The deep petrosal nerve (postganglionic sympathetic fibres) and the
greater petrosal nerve (preganglionic parasympathetic fibres) converge
to form the nerve of the pterygoid canal (Vidian nerve in the Vidian
canal). The canal enters the pterygopalatine fossa, and the nerve joins
the pterygopalatine ganglion, where the parasympathetic fibres synapse,
but the sympathetic fibres pass through without synapsing (Ch. 32).
The nerve of the pterygoid canal is an important landmark to the
petrous portion of the internal carotid artery, and may also rarely be
transected to treat intractable rhinorrhoea. Sympathetic postganglionic
vasomotor fibres are distributed to the nasal blood vessels. Postgangli-
onic parasympathetic fibres derived from the pterygopalatine ganglion A
provide the secretomotor supply to the nasal mucous glands, and are
distributed via branches of the maxillary nerves.
3
Olfactory nerves
Olfactory nerves are bundles of very small axons derived from olfac-
tory receptor neurones in the olfactory mucosa. The axons are un-
myelinated, and in varying stages of maturity, reflecting the constant
turnover of olfactory neurones that takes place in the olfactory epithe-
lium. Bundles of axons surrounded by olfactory ensheathing cells form
a plexiform network in the subepithelial lamina propria of the mucosa.
The bundles unite into as many as 20 branches that cross the cribri-
form plate in lateral and medial groups, and enter the overlying olfac-


tory bulb, where they end in glomeruli. Each branch is ensheathed by
dura mater and pia arachnoid as it passes through the cribriform plate
(Fig. 33.12). The dura subsequently becomes continuous with the
nasal periosteum, and the pia arachnoid merges with the connective
tissue sheaths surrounding the nerve bundles, an arrangement that
may favour the spread of infection into the cranial cavity from the
nasal cavity.
In severe injuries involving the anterior cranial fossa, the olfactory
bulb may be separated from the olfactory nerves or the nerves may be
torn, producing anosmia, i.e. loss of olfaction. Fractures may involve
the meninges, so that cerebrospinal fluid may leak into the nose, result- B
ing in cerebrospinal rhinorrhoea. Such injuries open up avenues for
intracranial infection from the nasal cavity. 3
Vomeronasal organ
Available with the Gray’s Anatomy e-book
PARANASAL SINUSES
The paranasal sinuses are the frontal, ethmoidal, sphenoidal and maxil-
lary sinuses, housed within the bones of the same name (see Fig. 33.1;
Figs 33.13–33.15). They all open into the lateral wall of the nasal cavity
by small apertures that permit both the equilibration of air between the
various air spaces and the clearance of mucus from the sinuses into the
nose via a mucociliary escalator. The detailed position of these aper-
tures, and the precise form and size of each of the sinuses, vary enor-
mously between individuals (Lang 1989, Beale et al 2009, Navarro
1997). Respiratory epithelium extends through the apertures of the
paranasal sinuses to line their cavities, a feature that unfortunately
favours the spread of infections. Sinus mucosa is thinner and less vas-
cular, and has fewer goblet cells, than nasal mucosa. Cilia are always C
present in the mucosa near the apertures but less evenly distributed
elsewhere within the sinuses. Fig. 33.12 Axial (A, B) and sagittal (C) scans through the olfactory groove.


The functions of the paranasal sinuses remain speculative. They A, Computed tomogram (CT). B–C, Magnetic resonance fast imaging
clearly add some resonance to the voice, and also allow the enlargement employing steady-state acquisition (FIESTA) sequence. Key: 1, ethmoid
of local areas of the skull while minimizing a corresponding increase plate; 2, inferior orbital fissure; 3, olfactory bulb. (With permission from
in bony mass. It is likely that such growth-related changes serve to Linn J Cranial nerves. In: Naidich TP, Castillo M, Cha S, Smirniotopoulos
strengthen particular regions, e.g. the alveolar processes of the maxillae JG (eds) Imaging of the Brain. 2013, Elsevier, Saunders.)
when the secondary dentition erupts, but they may also function in


Nose, nasal cavity and paranasal sinuses
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In most amphibians, reptiles and mammals, the vomeronasal organ is
the peripheral sensory organ of the accessory olfactory system. In these
animals, paired vomeronasal organs are located either at the base of the
nasal septum or in the roof of the mouth, and are involved in chemical
communication that is often, but not exclusively, mediated via phero-
mones. In many macrosomatic animals, the vomeronasal organ con-
sists of a vomeronasal duct that contains chemosensory cells, and a
vomeronasal nerve that terminates centrally in the accessory olfactory
bulb. The vomeronasal organ exists in the developing human fetus but
its existence in the adult has long been controversial. A bilateral struc-
ture in the anteroinferior wall of the nasal septum just dorsal to the
paraseptal cartilages, which is presumed to be analogous to the vomero-
nasal organ of other vertebrates, has been demonstrated in adult human
tissue; while there is no evidence that this structure has any neurorecep-
tive function, it has been suggested that it might have an as yet unknown
endocrine function (Wessels et al 2014).


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Superior concha Crista galli
Posterior ethmoidal sinus Anterior ethmoidal sinus
Frontal sinus
Middle concha Middle ethmoidal sinus
Accessory orifice of Orifice of maxillary
maxillary sinus sinus in hiatus semilunaris
Infraorbital nerve
Uncinate process
of ethmoid
Maxillary sinus
Inferior concha
Fig. 33.13 A coronal section through the nasal cavity, viewed from the posterior aspect. The plane of the section on the right side is more anterior.
The normal orifice of the maxillary sinus is shown on the right side and an accessory orifice on the left side.
Foramen rotundum Anterior clinoid process Understanding the development of the sinuses at each stage of child-
hood is essential for interpreting pathology and planning surgery.
Cadaveric and radiological studies have provided normative data for
sinus development.
Birth
Available with the Gray’s Anatomy e-book
1–4 years
S S
Available with the Gray’s Anatomy e-book
4–8 years
C C
Available with the Gray’s Anatomy e-book
8–12 years
Available with the Gray’s Anatomy e-book
Variations in sinus development
Available with the Gray’s Anatomy e-book
Lateral pterygoid plate Medial pterygoid plate Pterygoid (Vidian) canal
Fig. 33.14 A coronal CT scan showing the sphenoidal air sinus. FRONTAL SINUS
Abbreviations: C, posterior choanae; S, sphenoidal sinus.
The paired frontal sinuses are posterior to the superciliary arches,
between the outer and inner tables of the frontal bone (see Figs 33.13,
contouring the head to provide visual signals indicating the individual’s 33.15A, B). Each usually underlies a triangular area on the surface of
status in a social context (e.g. gender, sexual maturity and group the face, its angles formed by the nasion, a point 3 cm above the nasion
identity). and the junction of the medial third and lateral two-thirds of the
Most sinuses are rudimentary or absent at birth, but enlarge appreci- supraorbital margin. The two sinuses are rarely symmetric, since the


ably during the eruption of the permanent teeth and after puberty, septum between them usually deviates from the median plane. Each
events that significantly alter the size and shape of the face. sinus may be further divided into a number of communicating recesses
by incomplete bony septa.
The average dimensions of an adult frontal sinus are: height 3.2 cm;
DEVELOPMENT OF THE PARANASAL SINUSES,
breadth 2.6 cm; and depth 1.8 cm. Each usually has a frontal portion
AND ANATOMICAL VARIATIONS IN CHILDHOOD that extends upwards above the medial part of the eyebrow, and an
orbital portion that extends back into the medial part of the roof of the
At birth, both small ethmoidal and maxillary sinuses are present, but orbit. One or both sinuses may rarely be hypoplastic or even absent;
the frontal sinus is nothing more than an out-pouching from the racial differences have been reported. The prominence of the supercil-
nasal cavity, and there is no pneumatization of the sphenoid bone. iary arches is no indication of the presence or size of the frontal sinuses.


Nose, nasal cavity and paranasal sinuses
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The turbinates at birth are usually bulky and the inferior and middle
meatuses are underdeveloped. The uncinate, hiatus semilunaris and
ethmoidal bulla are already well-defined, fixed landmarks, and both the
anterior and posterior ethmoidal cells are already almost completely
developed in terms of number but not size. The cells are separated by
connective tissue, which becomes compressed with subsequent expan-
sion of the cells. The ethmoid complex ranges from 8 to 12 mm in
length, 1 to 3 mm in width and 1 to 5 mm in height; the complexes
expand rapidly in size in the first few years of life. The maxillary sinus
is roughly spherical, with a volume of 6–8 cm3, and measures 10 mm
in length, 4 mm in height and 3 mm in width. It lies initially medial
to the orbit, but projects laterally under the orbit by the end of the first
year of life. The sphenoid is devoid of air, although a blind mucosal sac
may sometimes be identified. At birth, the sphenoid has two major
ossification centres; failure of fusion between the two may give rise to
anatomical variations such as a persistent ‘craniopharyngeal canal’. The
Eustachian tube is found within the nasal cavity, behind the posterior
end of the inferior turbinate. The frontal sinus is no more than a small
out-pouching that drains into the infundibulum.
The supreme turbinate has usually disappeared, while the remaining
three turbinates reduce relatively in size. The inferior meatus develops
and contributes to the nasal airway. The maxillary sinus enlarges rapidly
up to the age of 4 years, reaching laterally as far as the infraorbital canal,
and inferiorly to the attachment of the inferior turbinate; it ranges
between 22 and 30 mm in length, 12 and 18 mm in height and 11 and
19 mm in width. The ethmoidal cells enlarge in all directions, starting
anteriorly and then progressing posteriorly. By the age of 4, they are
well developed; variants such as the agger nasi cell, infraorbital cell and


concha bullosa are identifiable. Sphenoidal pneumatization com-
mences around 7 months of age; a distinct cell is visible by the age of
2 years. By 4 years of age, it is roughly pea-sized, with a diameter of
4–8 mm. The frontal sinus is the last to develop and is imperceptible
in infants less than 1 year old. It begins to pneumatize after the age of
2, gradually enlarging as an out-pouching from the anterior ethmoids.
Early growth is slow; by 4 years, the vertical height reaches only
half the height of the orbit (between 6 and 9 mm in height) (Wolf
et al 1993).
By 8 years, the sinuses have expanded in all directions. The maxillary
sinus has reached the maxillary bone laterally and the plane of the hard
palate, becoming tetrahedral in shape. It ranges from 34 to 38 mm in
length, 22 to 26 mm in height and 18 to 24 mm in width. The dental
buds of unerupted teeth are closely related to the floor of the sinus. The
ethmoidal cells continue to enlarge, but more slowly than before; the
posterior cells become larger than the anterior cells.
Pneumatization into the vertical plate of the frontal bone does not
usually begin until the fifth year, at which time the frontal sinus may
be identified radiologically. The frontal sinus pneumatizes rapidly and
begins to pneumatize into the vertical plate of the frontal bone; its
height reaches the orbital roof at 8 years (Ruf and Pancherz 1996).
By 12 years, the sinuses have almost reached adult proportions. The
maxillary sinus pneumatizes into the maxillary alveolus after eruption
of the permanent dentition, so that the floor of the sinus now sits
4–5 mm below the level of the floor of the nasal cavity. The ethmoidal
sinuses reach adult size, and the frontal sinuses extend into the frontal
bone, continuing to enlarge until puberty. The sphenoidal sinus reaches
its full size by the age of 14 years.
Asymmetry in the size and shape of the sinuses, hypoplasia and ana-
tomical variants are common (Navarro 1997). Unilateral or bilateral


maxillary hypoplasia occurs infrequently; the condition is rarely bilat-
eral. Pneumatization of an ethmoidal cell into the middle concha
creates a concha bullosa, and inferolaterally creates an infraorbital cell.
The degree of pneumatization of the sphenoid is highly variable but
aplasia is very rare. In contrast, unilateral aplasia of the frontal sinus is
present in 15% of adults, and present bilaterally in 5%.


Paranasal sinuses
567
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RETPAHC
Frontal sinus Agger nasi (anterior ethmoidal air cell) Sphenoidal sinus Inferior concha Middle concha Ethmoidal bulla
*
*
Fig. 33.17 A coronal CT scan through the ostiomeatal complex. Red
arrows indicate the direction of mucociliary flow; the blue area, the middle
meatus; and the green stars, the infundibulum.
A
Ethmoidal sinuses Orbital fat
Frontal sinus Ethmoidal bulla Posterior ethmoidal cells
B
Middle concha Inferior concha Hiatus semilunaris Sphenoidal sinus
Fig. 33.15 A–B, Sagittal CT scans showing the frontal, ethmoidal and
sphenoidal sinuses. Arrows indicate the hiatus semilunaris in A.
(A, Courtesy of Professor D Bell.)
Sphenoidal sinus Internal carotid artery
Nasal septum
They are more prominent in males, and lend the forehead an obliquity
Fig. 33.18 A horizontal section of the head showing the ethmoidal and
that contrasts with the vertical or convex profile typical of children and
sphenoidal sinuses. (With permission from Berkovitz BKB, Moxham BJ
females. 2002 Head and Neck Anatomy. London: Martin Dunitz.)
The aperture of each frontal sinus opens either into the anterior part
of the corresponding middle meatus by the ethmoidal infundibulum
as a frontonasal recess (rather than a duct), or medial to the hiatus
Vascular supply, lymphatic drainage
semilunaris if the uncinate process is attached to the lateral nasal wall
or an agger nasi cell (Kuhn 2002). The frontal recess is actually the most and innervation
anterior part of the anterior ethmoidal complex but is described here The frontal sinuses receive their arterial supply from the supraorbital
because of its importance in the drainage of the frontal sinus. Its lateral and anterior ethmoidal arteries. The veins drain into an anastomotic
wall is the lamina papyracea; the medial wall is formed by the middle vein in the supraorbital notch that connects the supraorbital and su-


turbinate; and posteriorly, the wall is made up of either the cranial base, perior ophthalmic veins. Lymphatic drainage is to the submandibular
in a suprabullar recess, or the insertion of the bulla, if this reaches the nodes. The sinuses are innervated by branches of the supraorbital nerves
cranial base. Anteriorly, the wall extends from the frontal sinus proper (general sensation) and the orbital branches of the pterygopalatine
to the anterior attachment of the middle turbinate. In its simplest form, ganglia (parasympathetic secretomotor fibres).
it takes the shape of an inverted funnel, forming an hourglass shape
with the floor of the frontal sinus. However, the frontal recess is often
narrowed both from in front and from behind by anterior ethmoidal SPHENOIDAL SINUS
cells, such that it may be highly convoluted (Fig. 33.16). These fronto-
ethmoidal cells are classified with regard to their attachments to the The sphenoidal sinuses are two large, irregular cavities within the body
inner walls of the frontal sinus and relationship to the frontal recess as of the sphenoid and therefore lie posterior to the upper part of the nasal
anterior or posterior, medial or lateral (Lund et al 2014). cavity (see Figs 33.14–33.15; Figs 33.17–33.18). Each opens into the


Nose, nasal cavity and paranasal sinuses
567.e1
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RETPAHC
F
A B C
Fig. 33.16 A, A coronal CT demonstrating the frontal sinus (F), agger nasi cell (blue arrow) and uncinate process inserting into the middle turbinate
(yellow arrow). B, An absent frontal sinus (asterisk). C, A coronal CT demonstrating variations in the frontal sinus with multiple cells within the frontal
recess.


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NoiTCEs
corresponding sphenoethmoidal recess via an aperture high on the and therefore it forms a rather tortuous barrier between them. Within
anterior wall of the sinus. The sphenoid ostium is usually medial to each group, the sinuses are only partially separated by incomplete bony
the superior turbinate, although the height of the ostium is highly vari- septa.
able. The average dimensions of the adult sphenoid are: vertical height
2 cm; transverse breadth 1.8 cm; and anteroposterior depth 2.1 cm. The Anterior ethmoidal sinuses
sinuses are usually separated by a septum that usually deviates from the Up to 11 anterior ethmoidal air cells drain into the ethmoidal infundibu-
midline, so that they are unequal in size and form. Their lumina may lum, a three-dimensional, funnel-shaped cleft between the uncinate
be further partially divided by bony laminae and accessory septa, espe- and lateral wall of the nose, by one or more orifices. The most anterior
cially in the region of former synchondroses, and these septa commonly group, developmental remnants of the first ethmoturbinals, are the
insert on to the internal carotid artery. Occasionally, one sinus overlaps agger nasi cells. These cells are almost always present. They are medial
the other above and, rarely, they intercommunicate. Bony ridges, pro- relations of the lacrimal sac and duct, and invaginate beneath the
duced by the internal carotid artery, pterygoid canal, maxillary branch frontal sinus on the lateral wall of the nasal cavity anteriorly. Removal
of trigeminal and sometimes the optic nerve, may project into the of the superior walls of the agger nasi, ‘uncapping the egg’, is a key part
sinuses from their lateral walls. The sphenoidal sinuses are related of surgery of the frontal recess. The ethmoidal bulla, arising from the
above to the optic chiasma and hypophysis cerebri, and on each side second ethmoturbinal of the nose, consists of a group of the largest and


to the internal carotid artery and cavernous sinus. One or both sinuses least variable anterior ethmoidal cells. The cleft between the posterior
may partially encircle the optic canal. Dehiscences in the osseous walls edge of the uncinate bone and the face of the ethmoidal bulla is known
may occasionally leave their mucosa in contact with the overlying dura as the hiatus semilunaris. When the bullar lamella reaches the cranial
mater, optic nerve or carotid artery. base, this forms the posterior wall of the frontal recess. In other cases,
The extent of pneumatization of surrounding bone is highly vari- a suprabullar recess may be found. Infraorbital (Haller) cells may
able. Sometimes, a lateral recess may extend into the greater and lesser develop medially beneath the orbital floor (Fig. 33.20).
wings of the sphenoid or the pterygoid processes, separating the ptery-
Posterior ethmoidal sinuses
goid (Vidian) canal and foramen rotundum, and may even invade the
basilar part of the occipital bone almost to the foramen magnum. A Up to seven posterior ethmoidal air cells usually drain by a single orifice
posterior ethmoidal sinus may extend posterosuperior to the relatively into the superior meatus; one may drain into the supreme meatus when
smaller sphenoidal sinuses. In such cases, the sphenoid is medial and present, and one or more into the sphenoidal sinus (Fig. 33.21). The
inferior to this sphenoethmoidal cell (Onodi cell), which itself will be posterior group lies very close to the optic canal and optic nerve; optic
closely related to the optic nerve and carotid artery. An attempt to nerve injury is a devastating potential complication of endoscopic sinus
approach the sphenoid through a sphenoethmoidal cell places these surgery, particularly if a sphenoethmoidal cell (Onodi cell) is present.
structures at risk of injury. Sphenoethmoidal cells are readily identified The reported incidence varies widely (3.5 to 51%), according to racial
on computed tomographic (CT) imaging, where a horizontal bar can group; it is more common in non-Caucasians. The sphenoethmoidal


be seen in the coronal plane. The anterior clinoid process may be pneu- cell is usually regarded as the most posterior ethmoidal cell that pneu-
matized in up to 15% of sphenoidal cells. matizes lateral and superior to the sphenoidal sinus, and is intimately
The shape and position of the sphenoidal sinus are of clinical associated with the optic nerve; it may contain a tuberculum nervi
importance in an endoscopic trans-sphenoidal surgical approach to optici, where the optic canal bulges into the wall of the cell.
the hypophysis cerebri. The sinuses may be classified into three main
types: sellar, the most common type, in which the sinus extends for Roof of the ethmoid
a variable distance beyond the tuberculum sellae; presellar, in which The ethmoid bone is open superiorly; the roof is closed by the orbital
the sinus occasionally extends posteriorly towards, but not beyond, the plate of the frontal bone. Ethmoidal air cells indent this plate; each
tuberculum sellae; and conchal, the rarest type, in which a small sinus one is a ‘fovea ethmoidalis’. The thin, lateral cribriform lamella (one of
is separated from the sella turcica by approximately 10 mm of trabec- the thinnest parts of the cranial base) forms the medial wall of the
ular bone. The anterior midline septum often becomes deviated to one roof, extending from the middle turbinate to the cribriform plate, and
side posteriorly; identification of this septation is important prior to the lateral wall of the olfactory fossa or niche. The olfactory fossa
surgery (Fig. 33.19). varies in depth and is frequently asymmetrical; it is at risk during sinus
surgery.
Vascular supply, lymphatic drainage
and innervation Uncinate process
The sphenoidal sinuses receive their arterial supply from the posterior The uncinate process in a thin, hook-shaped bone that articulates with
ethmoidal branches of the ophthalmic arteries and nasal branches of the perpendicular plate of the palatine bone and the ethmoidal process
the sphenopalatine arteries. Venous drainage is through the posterior of the inferior concha. Its posterosuperior margin is free, forming the


ethmoidal veins draining into the superior ophthalmic veins. Lymph hiatus semilunaris with the ethmoidal bulla. It may sometimes reflect
drainage is to the retropharyngeal nodes. The sinuses are innervated by medially into the middle meatus and usually overlies the ostium of the
the posterior ethmoidal branches of the ophthalmic nerves (general maxillary sinus. It is frequently removed during sinus surgery (Becker
sensation) and the orbital branches of the pterygopalatine ganglia 1994).
(parasympathetic secretomotor fibres).
Vascular supply and innervation
ETHMOIDAL SINUSES The ethmoidal sinuses receive their arterial supply from nasal branches
of the sphenopalatine artery and the anterior and posterior ethmoidal
branches of the ophthalmic artery. Venous drainage is by the corres-
The ethmoidal sinuses differ from the other paranasal sinuses in that
ponding veins. The lymphatics of the anterior group drain to the
they are formed of multiple thin-walled cavities in the ethmoidal laby-
submandibular nodes, and those of the posterior group to the retro-
rinth (see Figs 33.13, 33.15–33.18). The number and size of the cavities
pharyngeal nodes. The sinuses are innervated by the anterior and
vary, from 3 large to 18 small sinuses on each side. They lie between
posterior ethmoidal branches of the ophthalmic nerves (general sensa-
the upper part of the nasal cavity and the orbit, and are separated from
tion) and the orbital branches of the pterygopalatine ganglia (parasym-
the latter by the paper-thin lamina papyracea or orbital plate of the
pathetic secretomotor fibres).
ethmoid (this presents a poor barrier to infection, which may therefore
spread into the orbit). Pneumatization may extend into the middle
concha, or into the body and wings of the sphenoid bone lateral to the
sphenoidal sinus. (There is a view that the ethmoidal sinuses are aerated MAXILLARY SINUS
after birth, rather than pneumatized, as happens with the other para-


nasal sinuses (Jankowski 2013).) The maxillary sinus is the largest of the paranasal sinuses. It usually fills
The ethmoidal sinuses are divided clinically into anterior and pos- the body of the maxilla and is pyramidal in shape (see Figs 30.8B,
terior groups on each side, distinguished by their embryological devel- 33.13, 33.17; Fig. 33.22). The base is medial and forms much of the
opment, sites of communication with the nasal cavity, their mucociliary lateral wall of the nasal cavity. The floor, which often lies below the
drainage, and their relation to the basal lamella of the middle turbinate. nasal floor, is formed by the alveolar process and part of the palatine
(Cells wrongly designated previously as belonging to a middle group process of the maxilla. It is related to the roots of the teeth, especially
are now included with the anterior group (Stammberger and Kennedy the second premolar and first molar, but may extend posteriorly to the
1995).) The anterior and posterior groups are separated from each other third molar tooth and/or anteriorly to incorporate the first premolar,
by the basal lamella; this may be indented by cells from either group and sometimes the canine. Defects in the bone overlying the roots are


Nose, nasal cavity and paranasal sinuses
568.e1
33
RETPAHC
S S
A B
S
C D
Fig. 33.19 A, A coronal CT demonstrating a normal right-sided sphenoidal sinus and a small left-sided sphenoidal sinus (S). The left sphenoethmoidal
cell is also shown (asterisk). Pneumatization of the left anterior clinoid process (green arrow) means that the optic nerve (yellow arrow) lies exposed
within the sphenoethmoidal cell. The foramen rotundum (blue arrow) and pterygoid (Vidian) canal (red arrow) can also be seen. B, An endoscopic view of
a right Onodi cell; the optic nerve is visible in the posterolateral wall of the cell (asterisk). C, A coronal CT demonstrating well-pneumatized sphenoidal
sinuses. The foramen rotundum (asterisk) and internal carotid artery (arrow) are also shown. D, A sagittal CT demonstrating the sphenoidal sinus (S),
pituitary fossa (arrow) and posterior sphenoethmoidal cell (asterisk).
E
A
C
Fig. 33.20 A, The anterior ethmoidal air cells (E). B, An endoscopic view
showing a partially opened agger nasi cell (asterisk). C, An infraorbital
B ethmoidal cell (Haller cell, asterisk), seen as a variation of anterior
ethmoidal anatomy.


NosE, NAsAL CAviTy ANd PARANAsAL siNusEs
568.e2
4
NoiTCEs
A
B
Fig. 33.21 A, A coronal CT demonstrating the posterior ethmoidal cells.
A bony spur can be seen in the nasal septum. B, The posterior ethmoidal
air cells and the sphenoethmoidal recess (arrow).


Paranasal sinuses
569
33
RETPAHC
not uncommon. The roof of the sinus forms the major part of the floor posterior superior alveolar artery and the infraorbital artery form an
of the orbit. It contains the infraorbital canal, which may exhibit dehis- anastomosis in the bony wall of the sinus, which also supplies the
cences. The lateral truncated apex of the pyramid extends into the mucous membrane that lines the nasal chambers. An extraosseous
zygomatic process of the maxilla, and may reach the zygomatic bone, anastomosis frequently exists between the posterior superior alveolar
in which case it forms the zygomatic recess, which throws a V-shaped artery and the infraorbital artery. The intra- and extraosseous anasto-
shadow over the antrum on a lateral radiograph. moses form a double arterial arcade that supplies the lateral antral wall
The facial surface of the maxilla forms its anterior wall, and is and, partly, the alveolar process. Veins corresponding to the arteries
grooved internally by a delicate canal (canalis sinuosus) that houses drain into the facial vein or pterygoid venous plexus on either side.
the anterior superior alveolar nerve and vessels as they pass forwards Lymph drainage is to the submandibular nodes. The sinuses are inner-
from the infraorbital canal. The posterior wall is formed by the vated by the infraorbital and anterior, middle and posterior superior
infratemporal surface of the maxilla; it contains alveolar canals that alveolar branches of the maxillary nerves (general sensation), and nasal
may produce ridges in the sinus and that also conduct the posterior branches of the pterygopalatine ganglia (parasympathetic secretomotor
superior alveolar vessels and nerves to the molar teeth. The medial wall fibres).
is deficient posterosuperiorly at the maxillary hiatus, a large opening
that is partially closed in an articulated skull by portions of the perpen-
dicular plate of the palatine bone, the uncinate process of the ethmoid IMAGING OF THE PARANASAL SINUSES
bone, the inferior nasal concha, the lacrimal bone and the overlying
nasal mucosa, to form an ostium and anterior and posterior fonta- Standard radiological images are no longer recommended in the diag-


nelles. The ostium usually opens into the inferior part of the ethmoidal nosis of rhinosinusitis because of their poor specificity and sensitivity,
infundibulum, and thence into the middle meatus, via the hiatus semi- although they may be used to confirm the presence of acute frontal or
lunaris (the hiatus forms the area above the superior edge of the unci- maxillary sinusitis that has failed to respond to medical treatment and
nate process). The ostium is not normally visible on examination of requires urgent drainage. CT defines anatomical variations but should
the nose, without prior resection of the uncinate process. The fonta- not be used in isolation for diagnosis because 1 in 3 asymptomatic
nelles are covered only by periosteum and mucosa, and may contain individuals show incidental mucosal changes. Spiral CT provides good-
accessory ostia that may be visible on nasendoscopy and CT. All of the quality axial, coronal and sagittal images that facilitate an appreciation
openings are nearer the roof than the floor of the sinus, which means of the size and relationship of the paranasal sinuses (Fig. 33.23).
that the natural drainage of the maxillary sinus is reliant on an intact
mucociliary escalator; the cilia of the sinus mucoperiosteum normally
SPREAD OF INFECTION FROM THE SINUSES
beat towards the ostium.
The maxillary sinus may be incompletely divided by septa; complete
septa are very rare. The thinness of its walls is clinically significant in Uncontrolled paranasal sinus infection can cause very significant mor-
determining the spread of tumours from the maxillary sinus. A tumour bidity. In the pre-antibiotic era, it was often associated with mortality
may push up the orbital floor and displace the eyeball; project into the from meningitis and brain abscess. Paranasal sinus infection has the
nasal cavity, causing nasal obstruction and bleeding; protrude on to potential to spread to the orbit, cavernous sinuses, meninges and brain.
the cheek, causing swelling and numbness if the infraorbital nerve is The ability to overcome infection at this site depends on the virulence
damaged; spread back into the infratemporal fossa, causing restriction of the infecting organism, the speed with which appropriate treatment


of mouth opening due to pterygoid muscle damage and pain; or spread is delivered, innate immunity and individual anatomical aspects of the
down into the mouth, loosening teeth and causing malocclusion. sinuses that may predispose to spread of infection. Normal mucociliary
Extraction of molar teeth may damage the floor, and impact may frac- clearance of the nasal and paranasal mucosa becomes paralysed or
ture its walls. Rarely, hypoplasia of one maxillary antrum is present. uncoordinated very quickly with the onset of infection and patent or
potentially patent drainage pathways become paramount. The middle
Ostiomeatal complex
meatus forms the common drainage pathway for the anterior ethmoi-
The term ostiomeatal complex, or ostiomeatal unit, refers to the area dal, frontal and maxillary sinuses. The posterior ethmoidal and sphe-
that includes the maxillary sinus ostium, ethmoidal infundibulum and noidal sinuses drain into the superior meatus and sphenoethmoidal
the hiatus semilunaris (see Fig. 33.17); it is a functional complex rather recess. Endoscopic examination will usually show infected mucus
than a clearly defined anatomical structure (see Fig. 33.22A). The draining from these areas in this situation (Simmen and Jones 2005).
complex is the common pathway for drainage of secretions from the The bony walls of the sinuses are paper-thin in places and dehis-
maxillary and anterior group of ethmoidal sinuses; where the uncinate cences of them, particularly of the lamina papyracea and cribriform
process attaches to the lateral nasal wall, the complex also drains the plate of the ethmoids, the lateral wall of the sphenoid, and the orbital
frontal sinus. and posterior walls of the frontal sinus, bring infected sinus mucosa
into direct contact with orbital periosteum, the dura of the anterior
Vascular supply, lymphatic drainage
cranial fossa and the cavernous sinus. Septic thrombophlebitis then
and innervation develops and infection spreads rapidly by this route. Sequelae can
The arterial supply of the maxilla is derived mainly from the maxillary include blindness, intra- and extradural collections, cavernous sinus


arteries via the anterior, middle and posterior superior alveolar branches thrombosis, meningitis, frontal lobe abscess and osteomyelitis of the
and from the infraorbital and greater palatine arteries. Branches of the cranial vault if diploic veins are involved.
Bonus e-book images and table
Fig. 33.2 The adult male nose. A, Basal Fig. 33.8 C, A higher-power view of the Fig. 33.19 A, A coronal CT demonstrating a
view. B, Frontal view. expanded end of an olfactory receptor normal right-sided sphenoidal sinus and a
neurone. D, A section of human olfactory small left-sided sphenoidal sinus. B, An
Fig. 33.7 A, An endoscopic view of the epithelium immunostained with anti-OMP endoscopic view of a right Onodi cell; the
nasal cavity showing inferior and middle (olfactory marker protein). optic nerve is visible in the posterolateral
turbinates. B, A view of the middle meatus wall of the cell. C, A coronal CT
and left lateral wall of the nose. C, An Fig. 33.16 A, A coronal CT demonstrating demonstrating well-pneumatized sphenoidal
endoscopic view of the nose showing the the frontal sinus, agger nasi cell and sinuses. D, A sagittal CT demonstrating the
middle turbinate and the pneumatized uncinate process inserting into the middle sphenoidal sinus, pituitary fossa and
uncinate process in the middle meatus. turbinate. B, An absent frontal sinus. C, A posterior sphenoethmoidal cell.
D, An endoscopic view of the nose coronal CT demonstrating variations in the
demonstrating a deviated nasal septum frontal sinus with multiple cells within the Fig. 33.20 A, The anterior ethmoidal air
making contact with the left inferior frontal recess. cells. B, An endoscopic view showing a
turbinate. E, An endoscopic view of the partially opened agger nasi cell. C, An
posterior nasal space.
Continued


Nose, nasal cavity and paranasal sinuses
569.e1
33
RETPAHC
A B
S
M
C D
Fig. 33.22 A, A coronal section demonstrating the maxillary and anterior ethmoidal sinuses. The ostiomeatal complex (ringed) and infundibulum (yellow
arrow) are shown. The anterior ethmoidal artery can be seen leaving the orbit (red arrow). The uncinate process is also visible (green arrow). B, A coronal
CT demonstrating the maxillary sinuses and a right-sided, pneumatized middle concha (concha bullosa; asterisk). C, A sagittal CT demonstrating the
relationship between the posterior wall of the maxillary sinus (M), the pterygopalatine fossa (arrow) and a lateral extension of the sphenoidal sinus (S).
D, A sagittal CT showing the course of the infraorbital nerve through the maxillary sinus (arrow).


NosE, NAsAL CAviTy ANd PARANAsAL siNusEs
569.e2
4
NoiTCEs
E
S
O
Orbit
C
S
M
A B
F
P
E
S
MT
IT
C
Fig. 33.23 A, A coronal section of the skull. Medial rectus (purple arrow); inferior turbinate (yellow arrow); anterior ethmoidal air cells (green arrow).
Abbreviations: C, concha bullosa (pneumatized middle turbinate); M, maxillary sinus; O, olfactory cleft; S, nasal septum. B, An axial section of the skull.
Medial rectus (blue arrow); orbital apex (purple arrow). Abbreviations: E, ethmoidal sinus; S, sphenoidal sinus. C, A sagittal section of the skull.
Abbreviations: E, ethmoidal sinus; F, frontal sinus; IT, inferior turbinate; MT, middle turbinate; P, pituitary fossa; S, sphenoidal sinus.


NosE, NAsAL CAviTy ANd PARANAsAL siNusEs
570
4
NoiTCEs
Bonus e-book images and table—cont’d
infraorbital ethmoidal cell (Haller cell), seen ethmoidal sinuses. B, A coronal CT Fig. 33.23 A, A coronal section of the skull.
as a variation of anterior ethmoidal anatomy. demonstrating the maxillary sinuses and a B, An axial section of the skull. C, A sagittal
right-sided, pneumatized middle concha section of the skull.
Fig. 33.21 A, A coronal CT demonstrating (concha bullosa). C, A sagittal CT
the posterior ethmoidal cells. B, The demonstrating the relationship between the Table 33.1 Terminology.
posterior ethmoidal air cells and the posterior wall of the maxillary sinus, the
sphenoethmoidal recess. pterygopalatine fossa and a lateral extension
of the sphenoidal sinus. D, A sagittal CT
Fig. 33.22 A, A coronal section showing the course of the infraorbital nerve
demonstrating the maxillary and anterior through the maxillary sinus.
KEY REFERENCES
Becker S 1994 Applied anatomy of the paranasal sinuses with emphasis on Lund VJ, Stammberger H, Fokkens WJ et al 2014 European position paper
endoscopic sinus surgery. Ann ORL 103:3–32. on the anatomical terminology of the internal nose and paranasal
A review of serial cadaveric sections in three planes, analysed with specific sinuses. Rhinology 50:Supp 24:1–34.
attention to the anatomy of the paranasal sinuses as it pertains to A re-evaluation of the anatomical terms in common usage by endoscopic
endoscopic sinus surgery. sinus surgeons and comparison with Terminologia Anatomica.
Buck L, Axel R 1991 A novel multigene family may encode odorant recep- Navarro JAC 1997 The Nasal Cavity and Paranasal Sinuses: Surgical Anatomy.
tors: a molecular basis for odor recognition. Cell 65:175–87. Berlin: Springer.
The 2004 Nobel Prize in Physiology or Medicine was awarded to Axel and A study that emphasizes anatomical variations and their surgical


Buck for their discoveries of the genetic determinants of the olfactory importance, with CT imaging accompanying three-plane dissections.
receptors and the organization of the olfactory system in humans.
Oneal R, Beil R, Schlesinger J 1999 Surgical anatomy of the nose. Otolaryn-
Huizing E 2003 Incorrect terminology in nasal anatomy and surgery, sug- gol Clin N Am 32:145–79.
gestions for improvement. Rhinology 41:129–33. A classification of the subcutaneous tissue of the external nose is included in
A discussion of the limitations of the current nomenclature for the anatomy this discussion of surgical anatomy.
of the external nose, with suggestions for an improved terminology.
Simmen D, Jones N 2005 Manual of Endoscopic Sinus Surgery and its
Jafek BW 1983 Ultrastructure of human nasal mucosa. Laryngoscope 93: Extended Applications. Stuttgart: Thieme.
1576–99. An extensive range of clinical images illustrate operative sinus procedures.
A study that characterizes the normal ultrastructure of human nasal
Simmen DB, Jones NS 2010 Epistaxis. In: Flint PW, Haughey BH, Lund VJ
mucosa, emphasizing the differences between olfactory and respiratory
et al (eds) Cummings Otolaryngology: Head and Neck Surgery, 5th ed.
epithelia.
Elsevier, Mosby; Ch. 45, pp. 682–93.
Kuhn F 2002 Lateral Nasal Wall and Sinus Surgical Anatomy: Contemporary A description of the vascular anatomy of the nasal cavity and the surgical
Understanding. Maintenance Manual for Lifelong Learning, 2nd ed. approaches to control epistaxis.
American Academy of Otolaryngology/Head and Neck Surgery Founda-
Stammberger H, Kennedy DW (eds) 1995 Paranasal sinuses: anatomic ter-
tion; pp. 203–14.
minology and nomenclature. Ann Otol Rhinol Laryngol (Suppl 167)
Excellent descriptions and diagrams of sinus anatomy and common
104 Part 2:7–16.
variations.
A consensus on the preferred modern usage of potentially confusing or
Lang J 1989 Clinical Anatomy of the Nose, Nasal Cavity and Paranasal ambiguous terms in sinus anatomy.
Sinuses. Stuttgart: Thieme.
A study with the emphasis on exact measurements between surgical


landmarks, with application to surgical procedures.


Nose, nasal cavity and paranasal sinuses
570.e1
33
RETPAHC
REFERENCES
Akguner M, Barutcu A, Karaca C 1998 Adolescent growth patterns of the Lund VJ, Stammberger H, Fokkens WJ et al 2014 European position paper
bony and cartilaginous framework of the nose: a cephalometric study. on the anatomical terminology of the internal nose and paranasal
Ann Plast Surg 41:66–9. sinuses. Rhinology 50:Supp 24:1–34.
Babin E, Moreau S, de Rugy MG et al 2003 Anatomic variations of the arter- A re-evaluation of the anatomical terms in common usage by endoscopic
ies of the nasal fossa. Otolaryngol Head Neck Surg 128:236–9. sinus surgeons and comparison with Terminologia Anatomica.
Beale TJ, Madani G, Morley SJ 2009 Imaging of the paranasal sinuses and Navarro JAC 1997 The Nasal Cavity and Paranasal Sinuses: Surgical Anatomy.
nasal cavity: normal anatomy and clinically relevant anatomical vari- Berlin: Springer.
ants. Semin Ultrasound CT MR 30:2–16. A study that emphasizes anatomical variations and their surgical
Becker S 1994 Applied anatomy of the paranasal sinuses with emphasis on importance, with CT imaging accompanying three-plane dissections.
endoscopic sinus surgery. Ann ORL 103:3–32. Oneal R, Beil R, Schlesinger J 1999 Surgical anatomy of the nose. Otolaryn-
A review of serial cadaveric sections in three planes, analysed with specific gol Clin N Am 32:145–79.
attention to the anatomy of the paranasal sinuses as it pertains to A classification of the subcutaneous tissue of the external nose is included in
endoscopic sinus surgery. this discussion of surgical anatomy.
Boyce J, Eccles R 2006 Do changes in nasal airflow have any physiological Paik SI, Lehman MN, Seiden AM et al 1992 Human olfactory biopsy. The
or pathological effect on the nose and paranasal sinuses? A systematic influence of age and receptor distribution. Arch Otolaryngol Head Neck
review. Clin Otolaryngol 31:15–19. Surg 118:731–8.


Buck L, Axel R 1991 A novel multigene family may encode odorant recep- Ruf S, Pancherz H 1996 Development of the frontal sinus in relation to
tors: a molecular basis for odor recognition. Cell 65:175–87. somatic and skeletal maturity. A cephalometric roentgenographic study
The 2004 Nobel Prize in Physiology or Medicine was awarded to Axel and at puberty. Eur J Orthodont 18:491–7.
Buck for their discoveries of the genetic determinants of the olfactory
Saban Y, Amodeo CA, Hammou JC et al 2008 An anatomical study of the receptors and the organization of the olfactory system in humans.
nasal superficial musculoaponeurotic system: surgical applications in
Churchill SE, Shackleford LL, Georgi JN et al 2004 Morphological variation rhinoplasty. Arch Facial Plast Surg 10:109–15.
and airflow dynamics in the human nose. Am J Human Biol 16: Samoliński BK, Grzanka A, Gotlib T 2007 Changes in nasal cavity dimen-
625–38. sions in children and adults by gender and age. Laryngoscope 117:
Holbrook EH, Leopold DA, Schwob JE 2005 Abnormalities of axon growth 1429–33.
in human olfactory mucosa. Laryngoscope 115:2144–54. Simmen D, Jones N 2005 Manual of Endoscopic Sinus Surgery and its
Huizing E 2003 Incorrect terminology in nasal anatomy and surgery, sug- Extended Applications. Stuttgart: Thieme.
gestions for improvement. Rhinology 41:129–33. An extensive range of clinical images illustrate operative sinus procedures.
A discussion of the limitations of the current nomenclature for the anatomy
Simmen DB, Jones NS 2010 Epistaxis. In: Flint PW, Haughey BH, Lund VJ
of the external nose, with suggestions for an improved terminology.
et al (eds) Cummings Otolaryngology: Head and Neck Surgery, 5th ed.
Jafek BW 1983 Ultrastructure of human nasal mucosa. Laryngoscope 93: Philadelphia: Elsevier, Mosby; Ch. 45, pp. 682–93.
1576–99. A description of the vascular anatomy of the nasal cavity and the surgical


A study that characterizes the normal ultrastructure of human nasal approaches to control epistaxis.
mucosa, emphasizing the differences between olfactory and respiratory
Stammberger H, Kennedy DW (eds) 1995 Paranasal sinuses: anatomic ter-
epithelia.
minology and nomenclature. Ann Otol Rhinol Laryngol (Suppl 167)
Jankowski R 2013 The Evo-Devo Origin of the Nose, Anterior Skull Base and 104 Part 2:7–16.
Midface. Berlin: Springer. A consensus on the preferred modern usage of potentially confusing or
Kuhn F 2002 Lateral Nasal Wall and Sinus Surgical Anatomy: Contemporary ambiguous terms in sinus anatomy.
Understanding. Maintenance Manual for Lifelong Learning, 2nd ed. Wessels Q, Hoogland PV, Vorster W 2014 Anatomical evidence for an endo-
American Academy of Otolaryngology/Head and Neck Surgery Founda- crine activity of the vomeronasal organ in humans. Clin Anat 27:
tion; Dubuque: Kendall/Hunt Publishing Company; pp. 203–14. 856–60.
Excellent descriptions and diagrams of sinus anatomy and common
Wolf G, Anderhuber W, Kuhn F 1993 Development of the paranasal sinuses
variations.
in children: implications for paranasal sinus surgery. Ann Otol Rhinol
Lang J 1989 Clinical Anatomy of the Nose, Nasal Cavity and Paranasal Laryngol 102:705–11.
Sinuses. Stuttgart: Thieme. Zhai LJ, Bruintjes TD, Boschma T et al 1995 The interdomal ligament does
A study with the emphasis on exact measurements between surgical not exist. Rhinology 33:135–7.
landmarks, with application to surgical procedures.


CHAPTER
34
Pharynx
The pharynx is a 12–14 cm long musculomembranous tube shaped like branches of the external carotid artery, particularly the ascending pha
an inverted cone. It extends from the cranial base to the lower border ryngeal artery, but also from the ascending palatine and tonsillar
of the cricoid cartilage (the level of the sixth or seventh cervical verte branches of the facial artery, the maxillary artery (greater palatine and
bra), where it becomes continuous with the oesophagus. The width of pharyngeal arteries and the artery of the pterygoid canal) and dorsal
the pharynx varies constantly because it is dependent on muscle tone, lingual branches of the lingual artery. The pharyngeal veins begin in a
especially of the constrictors; at rest, the pharyngooesophageal junc plexus external to the pharynx, receive meningeal veins and a vein from
tion is closed as a result of tonic closure of the upper oesophageal the pterygoid canal, and usually end in the internal jugular vein. Lym
sphincter, and during sleep, muscle tone is low and the dimensions of phatic vessels from the pharynx and cervical oesophagus pass to the
the pharynx are markedly decreased (which may give rise to snoring deep cervical nodes, either directly or through the retropharyngeal or
and sleep apnoea). The pharynx is limited above by the posterior part paratracheal nodes. The motor and sensory innervation is principally
of the body of the sphenoid and the basilar part of the occipital bone, via branches of the pharyngeal plexus.
and it is continuous with the oesophagus below. Behind, it is separated The pharynx lies behind, and communicates with, the nasal, oral
from the cervical part of the vertebral column and the prevertebral and laryngeal cavities via the nasopharynx, oropharynx and laryngo
fascia, which covers longus colli and longus capitis, by loose connective pharynx, respectively (Figs 34.1–34.2). Its lining mucosa is continuous


tissue in the retropharyngeal space above and the retrovisceral space with that lining the pharyngotympanic tubes, nasal cavity, mouth and
below. larynx. The retropharyngeal and parapharyngeal spaces surround the
The muscles of the pharynx are three circular constrictors and three pharynx; the retropharyngeal space lies anterior to the prevertebral and
longitudinal elevators. The constrictors may be thought of as three alar fascia and thus to the alar, danger space that lies between them.
overlapping cones that arise from structures at the sides of the head and For further reading, including reviews of some of the more important
neck, and pass posteriorly to insert into a midline fibrous band, the historical literature, see Flint et al (2010), Graney et al (1998), Hollin
pharyngeal raphe. The arterial supply to the pharynx is derived from shead (1982), WoodJones (1940).
Sphenoid Pharyngotympanic tube
Internal carotid artery
Mastoid part of temporal bone
Nasal septum
Posterior nasal aperture
Tensor veli palatini
Levator veli palatini
Nasopharynx
Palatopharyngeus
Salpingopharyngeus
Superior constrictor
Musculus uvulae and
Oropharynx uvula
Posterior part of tongue
Palatine tonsil
Epiglottis
Aryepiglottic fold Stylopharyngeus
Cuneiform tubercle
Internal branch of
Corniculate tubercle
Laryngopharynx superior laryngeal nerve
Palatopharyngeus
Posterior cricoarytenoid
Tendon of origin of
longitudinal fibres Circular muscle
of oesophagus of oesophagus
Fig. 34.1 The nasopharynx, oropharynx and laryngopharynx, exposed by cutting the median pharyngeal raphe and reflecting the constrictor muscles
laterally on either side, posterior view. 571


Pharynx
572
4
nOITCES
A
Ostium of pharyngotympanic tube Salpingopalatine fold
Pharyngeal tonsil
Sphenoid, body
Salpingopharyngeal fold
Atlas vertebra
Soft palate
Palatopharyngeal fold
Genioglossus
Occipital bone
Transverse ligament, atlas
Palatine tonsil
Pharynx Geniohyoid
Mylohyoid
Retropharyngeal space
Hyoid bone
Epiglottis
Pre-epiglottic fat body
Cricoid cartilage, lamina
Thyroid cartilage
Vestibular and vocal folds
Cricoid cartilage, arch
Prevertebral layer,
cervical deep fascia Pretracheal layer, cervical deep fascia
Thyroid gland, isthmus
Inferior thyroid vein
Oesophagus
Trachea
Fig. 34.2 A, A sagittal section through
the head and neck, including the nasal
and oral cavities but excluding the
intracranial region. B, A corresponding
magnetic resonance image (MRI), which
also includes the posterior cranial fossa,
cerebellum and cervical spinal cord. Key:
1 6
1, hard palate; 2, soft palate; 3, uvula;
2
4, epiglottis; 5, hyoid bone; 6, dens of
3 axis; 7, lamina of cricoid cartilage; 8,
oesophagus. (A, With permission from
4 7 Waschke J, Paulsen F (eds), Sobotta
Atlas of Human Anatomy, 15th ed,
8 Elsevier, Urban & Fischer, 2013.)
5
B
NASOPHARYNX the two posterior nares, each of which measures approximately 25 mm
vertically and 12 mm transversely. Just within these openings lie the
posterior ends of the inferior and middle nasal conchael/turbinates
Boundaries
(Ch. 33). The nasopharynx has a roof, a posterior wall, two lateral walls
and a floor. These are rigid (except for the floor, which can be raised
The nasopharynx lies above the soft palate and behind the posterior or lowered by the soft palate), and the cavity of the nasopharynx is


nares, which allow free respiratory passage between the nasal cavities therefore never obliterated by muscle action, unlike the cavities of the
and the nasopharynx (see Figs 34.1–34.2). The nasal septum separates oro and laryngopharynx. The nasal and oral parts of the pharynx


nasopharynx
573
43
rETPahC
A Pterygomandibular raphe B
Cartilage of pharyngotympanic tube Sphenoidal sinus
Frontal sinus
Pharyngeal tonsil
Tensor veli palatini
Tensor veli palatini
Levator veli palatini
Ascending
palatine artery Levator veli palatini
Salpingopharyngeus
Palatoglossus
Styloglossus
Superior constrictor
Stylopharyngeus Superior constrictor
Palatopharyngeus
Passavant's muscle
(palatopharyngeal
sphincter)
Stylohyoid ligament
Levator veli palatini
Glossopharyngeal
nerve
Soft palate
Inferior constrictor
Posterior
Middle constrictor
layer
Palatopharyngeus
Anterior
Mucous membrane
of pharynx Epiglottis layer
Fig. 34.3 A, The interior of the pharynx, exposed by removal of the mucous membrane, sagittal section. The bodies of the cervical vertebrae have been
removed, the cut posterior wall of the pharynx retracted dorsolaterally and palatopharyngeus reflected dorsally to show the cranial fibres of the inferior
constrictor. The dorsum of the tongue has been pulled ventrally to display a part of styloglossus in the angular interval between the mandibular and the
lingual fibres of origin of the superior constrictor. B, Muscles of the left half of the soft palate and adjoining part of the pharyngeal wall, sagittal section.
communicate through the pharyngeal isthmus, which lies between the glossopharyngeal, vagus, accessory and hypoglossal nerves lie within
posterior border of the soft palate and the posterior pharyngeal wall. the upper part of the carotid sheath and they come to lie within the
Elevation of the soft palate and constriction of the palatopharyngeal superior part of the parapharyngeal space, along with the sympathetic
sphincter close the isthmus during swallowing. chain. The foramen lacerum lies superolateral to the fossa of Rosen


The roof and posterior wall form a continuous concave slope that müller; in life, the foramen is closed by cartilage, over which the internal
leads down from the nasal septum to the oropharynx. It is bounded carotid artery runs. The foramen ovale, which transmits the mandibular
above by mucosa overlying the posterior part of the body of the sphen division of the trigeminal nerve, lies still further laterally; the mandibu
oid, and further back by the basilar part of the occipital bone as far as lar nerve passes through the parapharyngeal space and then the masti
the pharyngeal tubercle. Further down, the mucosa overlies the pharyn cator space in order to innervate the muscles of mastication. The
gobasilar fascia and the upper fibres of the superior constrictor, and retropharyngeal space is posterior to the nasopharynx.
behind these, the anterior arch of the atlas. A lymphoid mass, the pha
ryngeal tonsil (adenoid, nasopharyngeal tonsil), lies in the mucosa of Microstructure of non-tonsillar nasopharynx The nasopha
the upper part of the roof and posterior wall in the midline. ryngeal epithelium anteriorly is ciliated, pseudostratified respiratory in
The lateral walls of the nasopharynx display a number of important type with goblet cells (see Fig. 2.2D). The ducts of mucosal and sub
surface features. On either side, each receives the opening of the pha mucosal seromucous glands open on to its surface. Posteriorly, the
ryngotympanic tube (auditory or Eustachian tube), situated 10–12 mm respiratory epithelium changes to nonkeratinized stratified squamous
behind and a little below the level of the posterior end of the inferior epithelium which continues into the oropharynx and laryngopharynx.
nasal concha (see Fig. 34.2). The tubal aperture is approximately trian The transitional zone between the two types of epithelium consists of


gular in shape, and is bounded above and behind by the tubal elevation columnar epithelium with short microvilli instead of cilia. Superiorly,
that consists of mucosa overlying the protruding pharyngeal end of this zone meets the nasal septum; laterally, it crosses the orifice of the
the cartilage of the pharyngotympanic tube. A vertical mucosal fold, the pharyngotympanic tube; and it passes posteriorly at the union of the
salpingopharyngeal fold, descends from the tubal elevation behind the soft palate and the lateral wall. Numerous mucous glands surround
aperture (see Fig. 34.2) and covers salpingopharyngeus in the wall of the tubal orifices.
the pharynx (Fig. 34.3); a smaller salpingopalatine fold extends from
the anterosuperior angle of the tubal elevation to the soft palate in front Innervation Much of the mucosa of the nasopharynx behind the
of the aperture. As levator veli palatini enters the soft palate, it produces pharyngotympanic tube is supplied by the pharyngeal branch of the
an elevation of the mucosa immediately around the tubal opening (see pterygopalatine ganglion, which traverses the palatovaginal canal with
Fig. 34.3). A small variable mass of lymphoid tissue, the tubal tonsil, a pharyngeal branch of the maxillary artery.
lies in the mucosa immediately behind the opening of the pharyngo
tympanic tube. Further behind the tubal elevation is a variable depres
sion in the lateral wall, the lateral pharyngeal recess (fossa of PHARYNGEAL TONSIL
Rosenmüller), located between the posterior wall of the nasopharynx
and the salpingopharyngeal fold. The floor of the nasopharynx is The pharyngeal tonsil (adenoid, nasopharyngeal tonsil) is a median
formed by the nasal, upper surface of the soft palate. mass of mucosaassociated lymphoid tissue (MALT; see Ch. 4) situated
The relations of the nasopharynx are important in understanding in the roof and posterior wall of the nasopharynx (Fig. 34.4). At its


the spread of nasopharyngeal carcinoma (Chong and Ong 2008). The maximal size (during the early years of life), it is shaped like a truncated
mucosa of the nasopharynx is separated from the masticator space by pyramid, often with a vertically orientated median cleft, so that its apex
the parapharyngeal space. The carotid sheath, containing the carotid points towards the nasal septum and its base to the junction of the roof
space, lies posterior and lateral to the parapharyngeal space. The and posterior wall of the nasopharynx (Papaioannou et al 2013).