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SECTION IV
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Diseases of Pharynx
S e c t i o n o u t l i n e
47 Anatomy and Physiology of Pharynx, 269
48 Adenoids and Other Inflammations of Nasopharynx, 275
49 Tumours of Nasopharynx, 279
50 Acute and Chronic Pharyngitis, 287
51 Acute and Chronic Tonsillitis, 291
52 Head and Neck Space Infections, 297
53 Tumours of Oropharynx, 305
54 Tumours of the Hypopharynx and Pharyngeal Pouch, 309
55 Snoring and Sleep Apnoea, 313
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Chapter 47
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Anatomy and Physiology of Pharynx
PHARYNX IN GENERAL
Pharynx is a conical fibromuscular tube forming upper
part of the air and food passages. It is 12–14 cm long,
extending from base of the skull (basiocciput and basisphenoid) to the lower border of cricoid cartilage where it
becomes continuous with the oesophagus. The width of
pharynx is 3.5 cm at its base and this narrows to 1.5 cm at
pharyngo-oesophageal junction, which is the narrowest
part of digestive tract apart from the appendix.
STRUCTURE OF PHARYNGEAL WALL
(FIGURE 47.1)
From within outwards it consists of four layers:
1. Mucous membrane
2. Pharyngeal aponeurosis (pharyngobasilar fascia)
3. Muscular coat
4. Buccopharyngeal fascia
1. mucous membrane. It lines the pharyngeal cavity
and is continuous with mucous membrane of eustachian
tubes, nasal cavities, mouth, larynx and oesophagus. The
epithelium is ciliated columnar in the nasopharynx and
stratified squamous elsewhere. There are numerous mucous glands scattered in it.
2. pharyngeal aponeurosis (pharyngobasilar
Fascia). It is a fibrous layer which lines the muscular coat
and is particularly thick near the base of skull but is thin
and indistinct inferiorly. It fills up the gap left in the muscular coat near the base of skull.
3. muscular coat. It consists of two layers of muscles
with three muscles in each layer.
(a) External layer. It contains superior, middle and infe-
rior constrictor muscles.
(b) Internal layer. It contains stylopharyngeus, salpin-
gopharyngeus and palatopharyngeus muscles.
fibres. Between these two parts exists a potential gap called
Killian’s dehiscence. It is also called “gateway of tears” as
perforation can occur at this site during oesophagoscopy.
This is also the site for herniation of pharyngeal mucosa
in cases of pharyngeal pouch.
WALDEYER’S RING (FIGURE 47.2)
Scattered throughout the pharynx in its subepithelial layer
is the lymphoid tissue which is aggregated at places to
form masses, collectively called Waldeyer’s ring. The mass-
es are:
1. Nasopharyngeal tonsil or the adenoids
2. Palatine tonsils or simply the tonsils
3. Lingual tonsil
4. Tubal tonsils (in fossa of Rosenmüller)
5. Lateral pharyngeal bands
6. Nodules (in posterior pharyngeal wall).
PHARYNGEAL SPACES
There are two potential spaces in relation to the pharynx
where abscesses can form.
1. Retropharyngeal space, situated behind the pharynx
and extending from the base of skull to the bifurcation
of trachea (see p. 299).
2. Parapharyngeal space, situated on the side of pharynx.
It contains carotid vessels, jugular vein, last four cranial nerves and cervical sympathetic chain (see p. 301).
DIVISIONS OF PHARYNX
Anatomically, pharynx is divided into three parts
(Figure 47.3):
1. Nasopharynx
2. Oropharynx
3. Hypopharynx or laryngopharynx.
4. buccopharyngeal Fascia. It covers outer surface of
the constrictor muscles and in the upper part, it is also
prolonged forwards to cover the buccinator muscles.
Above the upper border of superior constrictor, it blends
with pharyngeal aponeurosis.
KILLIAN’S DEHISCENCE
Inferior constrictor muscle has two parts: thyropharyngeus
with oblique fibres and cricopharyngeus with transverse
NASOPHARYNX (EPIPHARYNX)
Applied Anatomy
Nasopharynx is the uppermost part of the pharynx and
therefore, also called epipharynx. It lies behind the nasal
cavities and extends from the base of skull to the soft palate or the level of the horizontal plane passing through
the hard palate (Figure 47.4).
1. Roof of the nasopharynx is formed by basisphenoid
and basiocciput.
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Figure 47.1. Structure of pharyngeal wall. From within outwards it
consists of (a) mucous membrane, (b) pharyngobasilar fascia, (c) muscular coat and (d) buccopharyngeal fascia.
SECTION IV — Diseases of Pharynx
Figure 47.2. Waldeyer’s ring.
Figure 47.4. Rathke’s pouch is represented by a dimple, high in
nasopharynx. Inferior to this, within the adenoid mass, is the nasopharyngeal bursa.
2. Posterior wall is formed by arch of the atlas vertebra
covered by prevertebral muscles and fascia. Both the
roof and the posterior wall imperceptibly merge with
each other.
3. Floor is formed by the soft palate anteriorly but is deficient posteriorly. It is through this space, the naso-
pharyngeal isthmus, that the nasopharynx communicates with the oropharynx.
4. Anterior wall is formed by posterior nasal apertures or
choanae, separated from each other by the posterior
border of the nasal septum. Posterior ends of nasal turbinates and meatuses are seen in this wall.
5. Lateral wall. Each lateral wall presents the pharyngeal
opening of eustachian tube situated 1.25 cm behind
the posterior end of inferior turbinate. It is bounded
above and behind by an elevation called torus tubarius
raised by the cartilage of the tube. Above and behind
the tubal elevation is a recess called fossa of Rosenmül-
ler, which is the commonest site for origin of carcinoma (Figure 47.5). A ridge extends from the lower end
of torus tubarius to the lateral pharyngeal wall and is
called salpingopharyngeal fold (Figure 47.9). It is raised
by the corresponding muscle.
Figure 47.3. Divisions of pharynx and the vertebrae related to their
posterior wall.
Nasopharyngeal Tonsil (Adenoids)
It is a subepithelial collection of lymphoid tissue at the
junction of roof and posterior wall of nasopharynx and
causes the overlying mucous membrane to be thrown
into radiating folds (Figure 47.1). It increases in size up to
the age of 6 years and then gradually atrophies.
Nasopharyngeal Bursa (Figure 47.4)
It is an epithelial-lined median recess found within the
adenoid mass and extends from pharyngeal mucosa to
the periosteum of the basiocciput. It represents the attachment of notochord to the pharyngeal endoderm during embryonic life. When infected, it may be the cause
of persistent postnasal discharge or crusting. Sometimes
an abscess can form in the bursa (Thornwaldt’s disease).
Rathke’s Pouch
It is represented clinically by a dimple above the adenoids
and is reminiscent of the buccal mucosal invagination, to
Figure 47.5. Endoscopic view of nasopharynx showing torus tubari-
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us in the lateral wall of nasopharynx. Note also the fossa of Rosenmüller which lies behind it. Fossa of Rosenmüller is the commonest site for
the origin of carcinoma nasopharynx.
form the anterior lobe of pituitary. A craniopharyngioma
may arise from it.
Tubal Tonsil
It is collection of subepithelial lymphoid tissue situated at
the tubal elevation. It is continuous with adenoid tissue
and forms a part of the Waldeyer’s ring. When enlarged
due to infection, it causes eustachian tube occlusion.
Sinus of Morgagni
It is a space between the base of the skull and upper free
border of superior constrictor muscle. Through it enters
(i) the eustachian tube, (ii) the levator veli palatini, (iii)
tensor veli palatini and (iv) ascending palatine artery—
branch of the facial artery (Figure 47.1).
Passavant’s Ridge
It is a mucosal ridge raised by fibres of palatopharyngeus.
It encircles the posterior and lateral walls of nasopharyngeal isthmus. Soft palate, during its contraction, makes
firm contact with this ridge to cut off nasopharynx from
the oropharynx during the deglutition or speech.
Epithelial Lining of Nasopharynx
Functionally, nasopharynx is the posterior extension of
nasal cavity. It is lined by pseudostratified ciliated columnar epithelium.
Lymphatic Drainage
Lymphatics of the nasopharynx, including those of the
adenoids and pharyngeal end of eustachian tube, drain
into upper deep cervical jugular nodes either directly or
indirectly through retropharyngeal and parapharyngeal
lymph nodes. They also drain into spinal accessory chain
of nodes in the posterior triangle of the neck. Lymphatics
of the nasopharynx may also cross midline to drain into
contralateral lymph nodes.
Functions of Nasopharynx
1. Acts as a conduit for air, which has been warmed and
humidified in the nose, towards its passage to the
larynx and trachea.
Chapter 47 — Anatomy and Physiology of Pharynx
2. Through the eustachian tube, it ventilates the middle
ear and equalizes air pressure on both sides of tympanic membrane. This function is important for hearing.
3. Elevation of the soft palate against posterior pharyngeal wall and the Passavant’s ridge helps to cut off nasopharynx from oropharynx. This function is important
during swallowing, vomiting, gagging and speech.
4. Acts as a resonating chamber during voice production.
Voice disorders are seen in nasopharyngeal obstruction
and velopharyngeal incompetence (see Chapter 63).
5. Acts as a drainage channel for the mucus secreted by
nasal and nasopharyngeal glands.
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OROPHARYNX
Applied Anatomy
Oropharynx extends from the plane of hard palate above
to the plane of hyoid bone below. It lies opposite the oral
cavity with which it communicates through oropharynge-
al isthmus. The latter is bounded above, by the soft palate;
below, by the upper surface of tongue; and on either side,
by palatoglossal arch (anterior pillar).
Boundaries of Oropharynx
1. posterior wall. It is related to retropharyngeal
space and lies opposite the second and upper part of the
third cervical vertebrae.
2. anterior wall. It is deficient above, where oropharynx
communicates with the oral cavity, but below it presents:
(a) Base of tongue, posterior to circumvallate papillae.
(b) Lingual tonsils, one on either side, situated in the base
of tongue. They may show compensatory enlargement following tonsillectomy or may be the seat of
infection.
(c) Valleculae. They are cup-shaped depressions lying
between the base of tongue and anterior surface of epiglottis. Each is bounded medially by the median glossoepiglottic fold and laterally by pharyngoepiglottic
fold (Figure 47.6). They are the seat of retention cysts.
3. lateral wall. It presents:
(a) Palatine (faucial) tonsil (for details, see p. 291).
(b) Anterior pillar (palatoglossal arch) formed by the pala-
toglossus muscle.
(c) Posterior pillar (palatopharyngeal arch) formed by the
palatopharyngeus muscle.
Both anterior and posterior pillars diverge from the soft
palate and enclose a triangular depression called tonsillar
fossa in which is situated the palatine tonsil (Figure 47.7).
Boundary between oropharynx above and the hy-
popharynx below is formed by upper border of epiglottis
and the pharyngoepiglottic folds.
Lymphatic Drainage
Lymphatics from the oropharynx drain into upper jugular chain particularly the jugulodigastric (tonsillar) node.
The soft palate, lateral and posterior pharyngeal walls and
the base of tongue also drain into retropharyngeal and
parapharyngeal nodes and from there to the jugulodigastric and posterior cervical group. The base of tongue may
drain bilaterally.
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SECTION IV — Diseases of Pharynx
Figure 47.8. Normal pyriform fossae right and left (arrows). They
show better when patient phonates.
Figure 47.6. Base of the tongue and valleculae.
Figure 47.7. Various structures seen in the oropharynx.
Functions of Oropharynx
1. As a conduit for passage of air and food.
2. Helps in the pharyngeal phase of deglutition.
3. Forms part of vocal tract for certain speech sounds.
4. Helps in appreciation of the taste. Taste buds are present in the base of tongue, soft palate, anterior pillars
and posterior pharyngeal wall.
5. Provides local defence and immunity against harmful
intruders into the air and food passages. This function
is subserved by subepithelial masses of lymphoid tissues scattered as Waldeyer’s ring. They are strategically
placed at the portals of air and food entry and act as
protective sentinels. B-lymphocytes in the germinal
centres of the follicles produce secretory antibodies of
IgA class whereas T-lymphocytes in parafollicular region produce cell-mediated immunity against various
viruses, bacteria and fungi. Pathogens which happen
to enter into these lymphoid masses are dealt by IgM
and IgG antibodies secreted by plasma cells.
HYPOPHARYNX (LARYNGOPHARYNX)
Applied Anatomy
Hypopharynx is the lowest part of the pharynx and lies behind and partly on the sides of the larynx. Its superior limit is the plane passing from the body of hyoid bone to the
posterior pharyngeal wall, while the inferior limit is lower
border of cricoid cartilage where hypopharynx becomes
continuous with oesophagus. Hypopharynx lies opposite
the third, fourth, fifth, sixth cervical vertebrae. Clinically,
it is subdivided into three regions—the pyriform sinus,
postcricoid region and the posterior pharyngeal wall.
1. Pyriform sinus (fossa). It lies on either side of the larynx and extends from pharyngoepiglottic fold to the
upper end of oesophagus.
It is bounded laterally by the thyrohyoid membrane
and the thyroid cartilage and medially by the aryepiglottic fold, posterolateral surfaces of arytenoid and cricoid cartilages (Figure 47.8). It forms the lateral channel
for food. Foreign bodies may lodge in the pyriform fossa. Internal laryngeal nerve runs submucosally in the
lateral wall of the sinus and thus is easily accessible for
local anaesthesia. It is also through this nerve that pain
is referred to the ear in carcinoma of the pyriform sinus.
2. Postcricoid region. It is the part of the anterior wall of
laryngopharynx between the upper and lower borders
of cricoid lamina. It is a common site for carcinoma
in females suffering from Plummer–Vinson syndrome
(Figure 47.9).
3. Posterior pharyngeal wall. It extends from the level
of hyoid bone to the level of cricoarytenoid joint.
Lymphatic Drainage
Pyriform sinus is richly supplied by lymphatics which
exit through the thyrohyoid membrane and drain into
the upper jugular chain.
Lymphatics of the posterior wall terminate in the lat-
eral pharyngeal or parapharyngeal nodes and thence to
the deep cervical lymph nodes.
Lymphatics of postcricoid region also drain into the
parapharyngeal nodes but may also drain into nodes of
supraclavicular and paratracheal chain.
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273
Figure 47.9. Pharynx opened from behind showing structures related to nasopharynx, oropharynx and laryngopharynx. Source. RL Drake,
AW Vogl, AWM Mitchell, 2017. Gray’s Anatomy for Students, 1SEA edition. Elsevier.
Rich lymphatic network of pyriform fossae explains
the high frequency with which nodal metastases are seen
in carcinoma of this region.
Functions of Hypopharynx
Laryngopharynx, like oropharynx, is a common pathway
for air and food, provides a vocal tract for resonance of
certain speech sounds and helps in deglutition. There is
coordination between contraction of pharyngeal muscles
and relaxation of cricopharyngeal sphincter at the upper end of oesophagus. Lack of this coordination, i.e.
failure of cricopharyngeal sphincter to relax when pharyngeal muscles are contracting causes hypopharyngeal
diverticulum.
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Chapter 48
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Adenoids and Other Inflammations
of Nasopharynx
ADENOIDS
ANATOMY AND PHYSIOLOGY
The nasopharyngeal tonsil, commonly called “adenoids”,
is situated at the junction of the roof and posterior wall of
the nasopharynx. It is composed of vertical ridges of lymphoid tissue separated by deep clefts (Figure 48.1). Covering epithelium is of three types: ciliated pseudostratified
columnar, stratified squamous and transitional. Unlike
palatine tonsils, adenoids have no crypts and no capsule.
Adenoid tissue is present at birth, shows physiological
enlargement up to the age of 6 years, and then tends to
atrophy at puberty and almost completely disappears by
the age of 20 (Figure 48.2).
In relation to sellaturcica, three types of pneumatization of sphenoid is seen: presellar, sellar and postsellar. This has a bearing on transnasal surgery of the
pitutary.
Blood supply. Adenoids receive their blood supply from:
1. Ascending palatine branch of facial.
2. Ascending pharyngeal branch of external carotid.
3. Pharyngeal branch of the third part of maxillary artery.
4. Ascending cervical branch of inferior thyroid artery of
thyrocervical trunk.
Lymphatics from the adenoid drain into upper jugular
nodes directly or indirectly via retropharyngeal and parapharyngeal nodes.
Nerve supply is through CN IX and X. They carry
sensation. Referred pain to ear due to adenoiditis is also
mediated through them.
AETIOLOGY
Adenoids are subject to physiological enlargement in childhood. Certain children have a tendency to generalized
lymphoid hyperplasia in which adenoids also take part.
Recurrent attacks of rhinitis, sinusitis or chronic tonsillitis may cause chronic adenoid infection and hyperplasia.
Allergy of the upper respiratory tract may also contribute to the enlargement of adenoids.
CLINICAL FEATURES
Symptoms and signs depend not merely on the absolute
size of the adenoid mass but are relative to the available
space in the nasopharynx.
Enlarged and infected adenoids may cause nasal, aural
or general symptoms.
1. Nasal Symptoms
(a) Nasal obstruction is the commonest symptom. This
leads to mouth breathing. Nasal obstruction also
interferes with feeding or suckling in a child. As
respiration and feeding cannot take place simultaneously, a child with adenoid enlargement fails to
thrive.
(b) Nasal discharge. It is partly due to choanal obstruc-
tion, as the normal nasal secretions cannot drain into
nasopharynx and partly due to associated chronic
rhinitis. The child often has a wet bubbly nose.
(c) Sinusitis. Chronic maxillary sinusitis is commonly
associated with adenoids. It is due to persistence of
nasal discharge and infection. Reverse is also true that
a primary maxillary sinusitis may lead to infected and
enlarged adenoids.
(d) Epistaxis. When adenoids are acutely inflamed,
epistaxis can occur with nose blowing.
(e) Voice change. Voice is toneless and loses nasal quality
due to nasal obstruction.
2. Aural Symptoms
(a) Tubal obstruction. Adenoid mass blocks the eustachian
tube leading to retracted tympanic membrane and
conductive hearing loss.
(b) Recurrent attacks of acute otitis media may occur due to
spread of infection via the eustachian tube.
(c) Chronic suppurative otitis media may fail to resolve in
the presence of infected adenoids.
(d) Otitis media with effusion. Adenoids form an impor-
tant cause of otitis media with effusion in children. The
waxing and waning size of adenoids causes intermittent eustachian tube obstruction with fluctuating
hearing loss. Impedance audiometry helps to identify
the condition.
3. General Symptoms
(a) Adenoid facies. Chronic nasal obstruction and mouth
breathing lead to characteristic facial appearance called
adenoid facies. The child has an elongated face with
dull expression, open mouth, prominent and crowded upper teeth and hitched up upper lip. Nose gives a
pinched-in appearance due to disuse atrophy of alaenasi
(Figure 48.3). Hard palate in these cases is highly arched
as the moulding action of the tongue on palate is lost.
(b) Pulmonary hypertension. Long-standing nasal obstruc-
tion due to adenoid hypertrophy can cause pulmonary hypertension and cor pulmonale.
(c) Aprosexia, i.e. lack of concentration.
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