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PHARYNX
LARYNX
06/06/2016
BAAB
The pharynx (plural: pharynges) is the part of
the throat that is behind the mouth and nasal
cavity and above the esophagus and the
trachea, or the tubes going down to the
stomach and the lungs.
 In humans the pharynx is part of the digestive
system and also of the conducting zone of the
respiratory system.
 The human pharynx is conventionally divided
into three sections: the nasopharynx, the
oropharynx and the laryngopharynx.
 It is also important in vocalization.
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Structurally, in humans there are two sets of pharyngeal
muscles that form the pharynx, determining the shape of its
lumen. These are arranged as an inner layer of longitudinal
muscles and an outer circular layer.
 Nasopharynx
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The upper portion of the pharynx of the nasopharynx,
which extend from the base of the skull to the upper surface
of the soft palate.
It includes the space between the internal nares and the soft
palate.
it lies above the oral cavity.
The adenoids, also known as the pharyngeal tonsils, are
lymphoid tissue structures located in the posterior wall of
the nasopharynx.
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The auditory tubes, which connect the middle ear to the
pharynx, open into the nasopharynx. The opening and
closing of the auditory tubes serves to equalize the
barometric pressure in the middle ear with that of the
ambient atmosphere.
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The anterior aspect of the nasopharynx communicates
through the choanae with the nasal cavities.
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The auditory tubes, open on its lateral walls forming
the pharyngeal openings
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Around the pharyngeal opening there are the mucosal
prominences and folds.
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Folds are the (i)salpingopharyngeal fold containing the
salpingopharyngeus muscle, and (ii) the
salpingopalatine fold containing the levator veli palatini
muscle.
The tensor veli palatini is lateral to the levator and does
not contribute the fold, since the origin is deep to the
cartilaginous opening.
On the posterior wall is a prominence, best marked in
childhood, produced by a mass of lymphoid tissue, which
is known as the pharyngeal tonsil.
pharyngeal bursa extend from the pharyngeal tonsil in the
midline to the basilar process of the occipital bone of the
skull.
Oropharynx
 lies behind the oral cavity extending from the
uvula to the level of the hyoid bone.
 It opens anteriorly into the mouth.
 its anterior wall consists of the base of the
tongue and the epiglottic vallecula;
 the lateral wall is made up of the tonsil,
tonsillar fossa, and tonsillar (faucial) pillars;
 the superior wall consists of the inferior
surface of the soft palate and the uvula.
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a flap of connective tissue called the epiglottis closes over the glottis
when food is swallowed to prevent aspiration.
 The oropharynx is lined by non-keratinised squamous stratified
epithelium.
Laryngopharynx:
 a.k.a. hypopharynx , is the caudal part of the pharynx; connecting the
pharynx to the esophagus.
 It lies inferior to the epiglottis and extends to the location where this
common pathway diverges into the respiratory (larynx- anteriorly)
and digestive (esophagus - posteriorly) pathways.
 During swallowing, food has the "right of way", and air passage
temporarily stops.
 the laryngopharynx serves as a passageway for food and air and is
lined with a stratified squamous epithelium. It is innervated by the
pharyngeal plexus.
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the laryngopharynx serves as a passageway for food and
air and is lined with a stratified squamous epithelium.
It is innervated by the pharyngeal plexus.
The vascular supply to the laryngopharynx includes the
superior thyroid artery, the lingual artery and the
ascending pharyngeal artery.
The primary neural supply is from both the vagus and
glossopharyngeal nerves
The vagus nerve provides a branch termed "Arnolds
Nerve" which also supplies the external auditory canal.
laryngopharyngeal cancer can result in referred otalgia.
This nerve is also responsible for the ear-cough reflex in
which stimulation of the ear canal results in a person
coughing.
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ACTIONS OF THE PHARYNGEAL MUSCLES
◦ During swallowing, successive contraction of the
superior, middle, and inferior constrictor muscles
helps to propel the bolus (ball) of food down into the
esophagus.
◦ In addition, contraction of the 3 longitudinal muscles
of the pharynx helps to raise the pharynx, effectively
aiding it in engulfing the bolus of food.
◦ In between acts of swallowing, the lowest fibers of
the inferior constrictor are thought to act as a
sphincter, guarding the entrance to the esophagus and
preventing the entry of air into the digestive system.
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The Larynx is an apparatus made up of cartilage,
ligaments, muscles, and mucous membrane,
which guards the entrance to the lower respiratory
passages (trachea, bronchi, and lungs) and houses
the vocal cords.
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The cartilages are forming the skeleton of the
larynx
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It is located within the anterior aspect of the neck,
anterior to the inferior portion of the pharynx and
superior to the trachea.
FUNCTION:
 The primary function is to:◦ protect the lower airway by closing abruptly
upon mechanical stimulation, thereby halting
respiration and preventing the entry of foreign
matter into the airway.
◦ Other functions of the larynx include the
production of sound (phonation)
◦ coughing
◦ the Valsalva maneuver
◦ control of ventilation
◦ acting as a sensory organ.
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STUCTURE:
The larynx is composed of
◦ 3 large, unpaired cartilages (cricoid, thyroid,
epiglottis);
◦ 3 pairs of smaller cartilages (arytenoids,
corniculate, cuneiform);
◦ a number of intrinsic muscles (see the
images below).
◦ The hyoid bone,(while technically not part
of the larynx), provides muscular
attachments from above that aid in laryngeal
motion.
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Cartilages:
◦ All cartilages of the larynx are of hyaline in nature except the
epiglottis which is the elastic cartilage.
1. Thyroid cartilage
◦ is the largest of the laryngeal cartilages.
◦ It is formed by a right and a left lamina that are separated
posteriorly and joined together at an acute angle in the
anterior midline, forming the laryngeal prominence
(Adam’s apple).
◦ The laryngeal prominence is more apparent in men, because
the angle between the 2 laminae is more acute in men (90°)
than in women (120°).
◦ The posterior aspect of each lamina is elongated to form a
superior horn and inferior horn.
◦ The medial surfaces of the inferior horns articulate with the outer
posterolateral surface of the cricoid cartilage.
◦ The inferior border is attached to the cricoid cartilage by the
cricothyroid membrane (midline) and the cricothyroid
muscles(either side).
◦ The superior horn and the entire superior edge is attached to the
hyoid bone by the thyrohyoid membrane.
2. Cricoid cartilage:
• The cricoid cartilage is a hyaline cartilage ring located at the
inferior aspect of the larynx being the only complete ring of
cartilage around the trachea.
• It has the shape of a "signet ring," with a broad portion
posterior to the airway (lamina of cricoid cartilage) and a
narrower portion circling anteriorly (arch of cricoid
cartilage).
• 2 oval depressions posteriorly for the attachment of
cricoarytenoid muscles which is separated by a vertical
midline ridge attaching the esophagus.
3. Arytenoid cartilages:
◦ The arytenoid cartilages form part of the larynx to which
the vocal ligaments and vocal folds attach.
◦ They are pyramidal in shape and have 3 surfaces, a base,
and an apex.
◦ They are located superior to the cricoid cartilage in the
posterior part of the larynx, with the base of the arytenoid
cartilages articulating on either side with the posterior aspect
of the upper border of the cricoid lamina.
◦ The anterior angle of the base of the arytenoid cartilage is
elongated to form a vocal process for attachment of the
vocal ligament
◦ The anterolateral surface has 2 depressions for attachment to
the false vocal cord (vestibular ligament) and the vocalis
muscle.
4. Corniculate cartilages:
◦ The corniculate cartilages are 2 small, conical cartilages
that articulate with the apices of the arytenoid
cartilages, serving to extend them posteriorly and
medially.
◦ They are located in the posterior parts of the
aryepiglottic folds of mucous membrane.
5. Cuneiform cartilages:
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The cuneiform cartilages are 2 small, club-shaped
cartilages that lie anterior to the corniculate cartilages in
the aryepiglottic folds.
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They form small, whitish elevations on the surface of the
mucous membrane just anterior of the arytenoid
cartilages.
6. Epiglottis:
• The epiglottis is a leaf-shaped elastic cartilage that moves down to
form a lid over the glottis and protect the larynx from aspiration of
foods or liquids being swallowed.
• It is attached via the thyroepiglottic ligament and projects
posterosuperiorly to cover the superior opening of the larynx.
• Its midline is also attached to the body of the hyoid bone via the
hyoepiglottic ligament.
• The depressions on either side of the median fold, between the
root of the tongue and the epiglottis, are called the valleculae
epiglottica.
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Ligaments of the larynx:
◦ Strong and broad ligaments are extrinsic, these are
 The thyrohyoid membrane. a broad fibroelastic ligament that
spans between the superior border of the thyroid cartilage
and the hyoid bone above.
 It contains an aperture on the lateral surfaces of each side
for the superior laryngeal arteries, nerves, and lymphatics.
 hyoepiglottic ligament: located anterosuperiorly, extending
from the midline of the superior surface of the epiglottis to
the body of the hyoid bone.
 The cricotracheal ligament connects the lower border of the
cricoid cartilage to the upper border of the first tracheal
cartilage ring.
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Cavities of the larynx
◦ Laryngeal cavity
 The laryngeal central cavity is tubular in shape and lined
with mucosa. Superiorly (laryngeal inlet) opens into the
pharynx and inferiorly is continuous with the lumen of the
trachea.
• The laryngeal cavity may be divided into 3 regions: the
vestibule which is the upper portion of the
cavity, between the laryngeal inlet and the
vestibular folds.
the middle, in the middle portion of the cavity, or
the voice box, is formed by the vestibular folds
above and the vocal folds below.
the infraglottic space, the lower portion of the
cavity, in between the vocal folds and inferior
opening of the larynx into the trachea.
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Laryngeal ventricles and saccules
◦ Found on either side of the middle laryngeal cavity, between
the vestibular and vocal folds.
◦ the walls of these saccules contain many mucous glands that
lubricate the vocal folds.
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Rima vestibuli and rima glottidis
◦ The rima vestibuli is the triangular-shaped opening between
the 2 adjacent vestibular folds.
 The apex lies anterior and the base is formed by the posterior
wall of the laryngeal cavity.
◦ The rima glottidis is a narrower, triangular-shaped opening that
lies beneath the rima vestibuli,
 formed by the 2 adjacent vocal folds.
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Piriform recesses
◦ The piriform recesses (piriform sinuses) are present on either
side of the anterolateral wall of the laryngopharynx.
◦ They are bounded medially by the aryepiglottic folds and
laterally by the thyroid cartilage and thyrohyoid membrane.
◦ They are a common place for food to become trapped.
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Laryngeal muscles:
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Cricothyroid
Posterior cricoarytenoid
Lateral cricoarytenoid
Transverse arytenoid – for adduction of the vocal cords
Thyroarytenoid
 All muscles are supplied by the reccurent laryngeal nerve
except the cricothyroid muscle supplied by the superior
laryngeal nerve.
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1.
2.
Laryngeal nerves:
Superior laryngeal nerve, arise from the inferior ganglia of the
vagus nerve and receive a branch from the superior cervical
sympathetic ganglion on each side in the upper neck.
Two branches, external laryngeal nerve- injury causes
hoarseness of the voice and an inability to produce high-pitched
sounds. Internal laryngeal nerve- sensory to laryngeal cavity
responsible for the cough reflex.
Recurrent laryngeal branch of the vagus nerve
The left recurrent laryngeal nerve originates in the thorax,
looping under the aortic arch before ascending, while the right
recurrent laryngeal nerve originates in the neck.
• Unilateral nerve damage presents with voice changes,
including hoarseness. Bilateral nerve damage may result in
aphonia (inability to speak) and breathing difficulties.
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Laryngeal dissorders:
◦ Endoscopic image of an inflamed human larynx
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Acute laryngitis is the sudden inflammation and swelling of the
larynx.
Chronic laryngitis is caused by smoking, dust, frequent yelling,
or prolonged exposure to polluted air.
Presbylarynx is a condition in which age-related atrophy of the
soft tissues of the larynx results in weak voice and restricted
vocal range and stamina.
Ulcers may be caused by the inflammation or infection
Polyps and nodules are small bumps on the vocal folds caused by
prolonged exposure to cigarette smoke and vocal misuse,
respectively.
Two related types of cancer of the larynx, namely squamous cell
carcinoma and verrucous carcinoma, are strongly associated
with repeated exposure to cigarette smoke and alcohol.
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Vocal cord paresis is weakness of one or both vocal folds.
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Laryngopharyngeal reflux is a condition in which acid from the
stomach irritates and burns the larynx. Similar damage can occur
with gastroesophageal reflux disease (GERD).
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Laryngomalacia is a very common condition of infancy, the soft,
immature cartilage of the upper larynx collapses inward during
inhalation, causing airway obstruction.
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Laryngeal perichondritis, the inflammation of the perichondrium
of laryngeal cartilages.
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Duchenne Muscular Dystrophy, intrinsic laryngeal muscles
(ILM) are spared from the lack of dystrophin and may serve as a
useful model to study the mechanisms of muscle sparing in
……………………….dystrophinopathy.