Download THE PHARYNX Internal Aspect

THE INTERIOR OF THE
PHARYNX
By
Dr. Muhammad Imran Qureshi
The Cavity

The cavity of the
pharynx is divided into:
1. The Nasal part (called
Nasopharynx)
2. The Oral part (called
the Oropharynx),
3. And the Laryngeal
part, (often called
Hypopharynx)
Nasopharynx
 The nasal part of the pharynx has a roof, lateral and
posterior walls.
 There is, essentially, no anterior wall, since the
choanae open here.
 The Roof, called the fornix, consists of mucous
membrane closely applied to the basal portions of the
sphenoid and occipital bones.
 The Lateral and Posterior walls consist of the superior
constrictors, the pharyngobasilar fascia that lines their
internal surfaces, and the mucosa.
Nasopharynx
 the floor of the anterior part of the nasal
pharynx is formed by the soft palate.
 It is the only really mobile wall of this part of
the pharynx
 Thus, the nasal pharynx remains constantly
open.
 Above the soft palate, on its each lateral wall
is the pharyngeal ostium / aperture /opening
of the auditory tube. (the tube to the middle
ear cavity)
Nasopharynx
 Above and posterior to
the ostium is an
elevation, the torus
tubarius, or tubal torus.
 It is produced by the
cartilage of the tube.
 Proceeding down from
the torus is a slight fold,
the salpingopharyngeal
fold (as it overlies the
salpingopharyngeus
muscle).
Nasopharynx
Nasopharynx
 Behind the torus and the
salpingopharyngeal fold is a slitlike
lateral projection/extension of the
pharynx, the pharyngeal recess.
 A small salpingopalatine fold runs from
the anterior border of the torus tubarius
toward the palate.
 Below the torus tubarius and in front of
the salpingopharyngeal fold is another
fold or bulge, the torus levatorius, or
levator torus.
 It is formed by the levator veli palatini
muscle and becomes especially
evident when the muscle contracts.
Nasopharynx
 Behind the soft palate, the nasopharynx opens into
the oral pharynx. This opening is usually called the
pharyngeal isthmus.
 At this level the nasal part of the pharynx can be
completely closed off from the oral part, as the soft
palate can be pulled backward and upward by the
levator veli palatini to meet the posterior wall.
 The meeting of soft palate and posterior pharyngeal
wall is necessary for proper phonation, especially of
consonants.
 It is also necessary if fluid swallowed under pressure
is to be kept from running into the nose (for instance,
one can drink bending over, or standing on one's
head, because of the complete closure here).
Nasopharynx
 In the posterior part of the roof and the upper part of the
posterior wall of the nasal part of the pharynx is an accumulation
of lymphoid tissue, the pharyngeal tonsil. This may be prominent
in children but becomes indistinct or disappears by adulthood.
 In children there is a similar accumulations of lymphoid tissue
associated with the posterior lip of the ostium of the auditory
tube which are called the tubal tonsils.
 When the pharyngeal and tubal tonsils are enlarged, they are
referred to as adenoids.
 These may cause difficulty in nasal breathing because of
obstruction of the nasal pharynx, and if the ostium of the
tube is occluded, there may be hearing loss because of
gradual absorption of the air in the middle ear cavity.
Oropharynx
 Above, behind the soft palate, the oral part of
the pharynx opens into the nasal part.
 Anteriorly, above, it opens into the oral cavity,
and below this, it is bordered by the dorsum
of the posterior one third of the tongue.
 Behind the tongue, the oral part of the
pharynx extends downward lateral and
posterior to the upwardly projecting epiglottis,
(a portion of the larynx), to become
continuous with the laryngeal part.
Oropharynx
 The fauces (throat):
 The lateral boundaries of the opening of the mouth
(faucial isthmus), into the pharynx, are called the
faucial pillars.
 Each pillar consists of two folds between which lies
the palatine tonsil.
 The anterior fold, called the palatoglossal arch,
curves downward and forward from the soft palate to
the tongue.
 The posterior fold, called the palatopharyngeal arch,
extends downward from the posterolateral border of
the soft palate along the wall of the pharynx.
Oropharynx
Oropharynx
 Each arch contains a similarly
named muscle, that is,
palatoglossus and
palatopharyngeus muscles.
 Between these two arches is
an almond shaped mass of
lymphoid tissue that
constitutes the palatine tonsil
and that largely fills the space
between the folds, the tonsillar
fossa.
 The roof and floor of the faucial
isthmus are not well defined.
However, they are the soft
palate and the dorsum of the
tongue.
Oropharynx
 A fold of mucous membrane
extends between the
palatoglossal and
palatopharyngeal arches
across the upper part of the
tonsil. It is called the
semilunar fold.
 Between it and the tonsil is a
slit, the supratonsillar fossa.
 A second fold, the triangular
fold, projects backward from
the palatoglossal arch and
either may be fused to the
tonsil or may leave a slit that
usually is called the anterior
tonsillar fossa.
Oropharynx
 The palatine tonsil varies considerably in size and shape.
 It may bulge markedly between the folds when inflamed or
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enlarged
Normally, it lies flat and almost hidden in the tonsillar fossa.
It often extends into the soft palate deep to the semilunar fold.
Its surface is covered with epithelium that has pits, the tonsillar
crypts, passing into the lymphoid substance.
The superior pharyngeal constrictor forms most of its muscular
bed. Between it and the tonsil is the pharyngobasilar fascia.
The part of the pharyngobasilar fascia adjacent to the tonsil
sends septa into it and often is described as the tonsillar
capsule.
Loose connective tissue between the “capsule” and the superior
constrictor muscle forms a line of cleavage that facilitates
removal of the tonsil.
Oropharynx
 The largest artery of the
tonsil is the tonsillar
branch of the facial
artery. It enters its lower
pole.
 The ascending
pharyngeal, lingual,
descending palatine and
ascending palatine
branch of the facial
usually also are
described as having
small tonsillar branches.
Oropharynx
 After passing across the gap
between the superior and middle
pharyngeal constrictors close to the
lower pole of the tonsil, the
glossopharyngeal nerve runs
forward to the tongue medial to the
hyoglossus muscle.
 Because of this relationship, edema
about the nerve may result from
tonsillectomy, and some patients
complain of temporary loss of taste
following this operation.
 The nerve gives off a tonsillar
branch which, along with branches
of the 9th from the pharyngeal
plexus, supplies the region of the
tonsil.
Oropharynx
 Below the fauces, the pharynx is bounded
anteriorly by the posterior part of the dorsum
of the tongue.
 This, in addition to presenting the vallate
taste buds, also has an accumulation of
lymphoid tissue beneath its mucosa.
 This lymphoid tissue on the pharyngeal
surface of the tongue constitutes the lingual
tonsil. It may also become sufficiently
enlarged to need removal when other tonsillar
tissue is removed.
Oropharynx
 The pharyngeal tonsils posteriorly and above,
the palatine tonsils laterally, and the lingual
tonsil anteriorly and below form an oblique
ring of lymphoid tissue around the pharynx,
called the “Waldeyer's ring”.
 This apparently has the function of tending to
halt infection at this level, but when it
becomes enlarged as a result of disease, it is
no longer of use as a defense mechanism,
and its enlargement may, of course, cause
obstruction.
Oropharynx
 Behind the tongue, the
epiglottis is united to it by
a midline and two lateral
folds, the median and the
lateral glossoepiglottic
folds, respectively.
 The paired depressions
between the median and
lateral glossoepiglottic
folds are the epiglottic
valleculae
Laryngopharynx
 The oral part of the pharynx is continuous with the
laryngeal part at the level of the upper border of the
epiglottis
 It is wide above but narrows rapidly below, at the
level of the lower border of the cricoid cartilage of the
larynx where it become continuous with the
esophagus.
 The anterior wall of this part of the pharynx is the
larynx:
Above is the posterior surface of the epiglottis and
below the opening into the larynx are certain
muscles of the larynx and the lamina or expanded
posterior part of the cricoid cartilage, covered
posteriorly by pharyngeal mucous membrane.
Laryngopharynx
Laryngopharynx
 The pharynx also extends
lateral to the larynx, being
separated from it by the
aryepiglottic folds that run from
the upper posterior border of
the larynx to the sides of the
epiglottis.
 These lateral extensions are
the piriform recesses (also
called sinuses / Fossae).
 As the pharynx narrows at the
cricoid level, the piriform
recesses are obliterated.
 Thus they are blind forward
extensions of the pharynx.
Laryngopharynx
 Each Piriform recess is a mucous lined space that is
bounded:
 Medially by the Quadrangular membrane of the larynx,
and
 Laterally,
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Above by the Thyrohyoid membrane, and
Below by the lamina of the Thyroid cartilage.
 A malignancy may develop in the space provided by the
Piriform fossa without producing symptoms, until the
patient presents with metastatic cervical
lymphadenopathy.
 The recesses are liable to be perforated by the
endoscope.
Laryngopharynx
 Since each epiglottic vallecula
is a shallow basin, an object
( safety pin etc.) that is thought
to have been swallowed or
inspired may sometimes lodge
in it, or such an object may
lodge in a piriform recess.
 Both the valleculae and the
recesses, therefore, usually are
examined for objects thought to
be inhaled, before a child is
subjected to bronchoscopy.
Laryngopharynx
 Swallowing (deglutition) is a complex act typically
involving contraction of the pharyngeal constrictors
and the esophagus from above downward.
 As the bolus is passed into the oral part of the
pharynx, the soft palate is raised to come in contact
with the posterior pharyngeal wall, and the pharynx
as a whole is raised by the action of its longitudinal
muscle.
 Contraction of the superior pharyngeal constrictor
passes the bolus into the region of the relaxed middle
constrictor, which in turn contracts, followed by the
inferior constrictor.
Laryngopharynx
 The cricopharyngeal part of the inferior
constrictor “cricoesophageal sphincter”
relaxes as swallowing is started, and a
descending contraction of the esophagus
passes the bolus into the stomach.
 The larynx is protected in part by contraction
of its sphincteric muscles and in part by the
fact that the food or liquid tends to pass to the
sides of the epiglottis rather than directly over
the laryngeal aditus