Anatomy of pharynx
Dr. Mohammad Mahmoud Mosaed
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Pharynx
•
Musculomembranous tube which is deficient anteriorly
extends From the base of the skull to the level of the 6th
cervical vertebra
•
It connects to the
•
•
Nasal cavity, mouth and Larynx
Function:
•
•
•
•
Passage way for food, air, water
Resonating chamber
Immune function, tonsils
It connects to the esophagus at the level of the 6th cervical
vertebra.
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Parts of the pharynx
The pharynx divided
into 3 parts
Nasopharynx behind
the nose
Oropharynx behind
the oral cavity
Laryngopharynx
behind the larynx
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Nasopharynx
•
Air passageway posterior to the nasal cavity extends from the base of the
skull to the level of the soft palate.
•
It communicates with the nose through the posterior nasal apertures
•
It communicates with the oropharynx through the oropharyngeal isthmus.
•
On each side (the lateral walls) it present the medial or pharyngeal opening
of the auditory (Pharyngotympanic) tube which connects the
nasopharynx with the tympanic cavity.
•
The elevation of the opening of the tube in the nasopharynx called tubal
elevation caused by cartilagenous part of the auditory tube
•
Around the tubal elevation there is a salpingopharyngeal fold caused by
salpingopharyngeal muscle and behind the fold there is a
salpingopharyngeal recess
•
Soft palate and uvula close nasopharynx during swallowing
•
In the submucosa of the roof is a collection of lymphoid tissue called the
pharyngeal tonsil (adenoids)
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Cribriform plate
of ethmoid
bone
Sphenoid
sinus
Posterior
nasal
aperture
Nasopharynx
Pharyngeal
tonsil
Opening of
pharyngotympani
c
tube
Uvul
a
Oropharynx
Palatine
tonsil
Isthmus of
the
fauces
Laryngopharynx
Esophagu
s
Trachea
(c) Illustration
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Frontal
sinus
Nasal cavity
Nasal conchae
(superior, middle
and inferior)
Nasal meatuses
(superior, middle,
and inferior)
Nasal
vestibule
Nostri
l
Hard
palate
Soft
palate
Tongue
Larynx
Epiglotti
s
Vestibular
fold
Thyroid
cartilage
Vocal fold
Cricoid
cartilage
Thyroid
gland
Lingual
tonsil
Hyoid
bone
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Oropharynx and laryngopharynx
• Oropharynx: Passageway for food and air, it lies behind the
•
oral cavity. It extends from the level of the soft palate to the
upper border of the epiglottis.
Isthmus of the fauces: opening of the oral cavity into the
oropharynx.
• Laryngopharynx: It extends from the level of the tip of the
•
epiglottis to the termination of the pharynx in the oesophagus
at the level of the 6th cervical vertebra.
On each side of the laryngeal inlet there is a depression called
piriform fossa bounded medially by the aryepiglottic fold and
laterally by lamina of the thyroid cartilage. Clinically, it is important
because it is a common site for the lodging of sharp ingested bodies such
as fish bones..
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Blood supply
•
Arteries
Arteries that supply upper parts of the pharynx include:
•
the ascending pharyngeal artery;
•
the ascending palatine and tonsillar branches of the facial artery;
•
numerous branches of the maxillary and the lingual arteries
All these vessels are from the external carotid artery.
Arteries that supply the lower parts of the pharynx include;
•
pharyngeal branches from the inferior thyroid artery, which originates from
the thyrocervical trunk of the subclavian artery.
•
Veins
•
Veins of the pharynx form a plexus, which drains superiorly into the
pterygoid plexus in the infratemporal fossa, and inferiorly into the facial and
internal jugular veins
•
Lymph drainage Lymphatic vessels from the pharynx drain into the deep
cervical nodes and include retropharyngeal (between nasopharynx and
vertebral column), paratracheal, and infrahyoid
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Motor innervation
All muscles of the pharynx are innervated by the vagus nerve
mainly through the pharyngeal plexus, except for the
stylopharyngeus, which is innervated by a branch of the
glossopharyngeal nerve .
Sensory innervation
Each subdivision of the pharynx has a different sensory
innervation:
The nasopharynx is innervated by a pharyngeal branch of the
maxillary nerve
The oropharynx is innervated by the glossopharyngeal nerve via
the pharyngeal plexus;
The laryngopharynx is innervated by the vagus nerve via the
pharyngeal plexus.
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Larynx
The larynx is an organ that provides a
protective sphincter at the inlet of the air
passage and is responsible for voice
production.
It extends from the tongue to the trachea
(from the level of the upper border of the
epiglottis to the level of the 6th cervical
vertebra)
Relations
Above it continuous with the pharynx
through the laryngeal inlet.
Below continuous with the trachea at the
level of 6th cervical vertebra
Anteriorly it is covered by skin, superficial
fascia, deep fascia and infrahyoid muscles
On each side it is related to the thyroid lobe
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Structure of larynx
• The framework of the
larynx is formed of
cartilages that are
held together by
ligaments
and
membranes, moved
by muscles, and
lined by mucous
membrane.
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Cartilaginous framework of the larynx
Three large unpaired
(single) cartilages
Thyroid
Cricoid
Epiglottis
Three
small
paired
cartilages
Arytenoid,
Corniculate
Cuneiform
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Thyroid cartilage
It is the largest of the laryngeal
cartilages. It is formed by a right and
a left laminae of hyaline cartilage,
which
are
widely
separated
posteriorly, but joined anteriorly.
The most superior point of the site of
fusion between the two laminae
projects forward as the laryngeal
prominence
('Adam's
apple').
which is more apparent in men. Just
superior to the laryngeal prominence,
the superior thyroid notch.
The posterior margin of each lamina
of the thyroid cartilage is elongated
to form a superior horn and an
inferior horn. The medial surface of
the inferior horn has a facet for
articulation with the cricoid cartilage;
The lateral surface of each thyroid
lamina is marked by a ridge (the
oblique line)
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Cricoid cartilage
The cricoid cartilage lies below
the
thyroid
cartilage
and
completely encircles the airway.
It is shaped like a 'signet ring'
with a broad lamina posterior and
a narrow arch anterior.
The lamina has 2 facets
The upper facet on its upper
bordet articulates with the base of
an arytenoid cartilage;
The lower facet on the lateral
surface of the lamina articulates
with the medial surface of the
inferior horn of the thyroid
cartilage.
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Epiglottis
This leaf-shaped lamina of elastic cartilage lies
behind the root of the tongue .
Its stalk is attached to the back of the thyroid
cartilage by the thyro-epiglottic ligament
The sides of the epiglottis are attached to the
arytenoid cartilages by the aryepiglottic folds of
mucous membrane.
The upper edge of the epiglottis is free.
The covering of mucous membrane passes
forward onto the posterior surface of the tongue
as the median glossoepiglottic fold; the
depression on each side of the fold is called the
vallecula .
Laterally the mucous membrane passes onto the
wall of the pharynx as the lateral glossoepiglottic
fold
The inferior half of the posterior surface of the
epiglottis is raised slightly to form an epiglottic
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tubercle
Arytenoid cartilages
The two arytenoid cartilages are pyramid-shaped cartilages
Each cartilage has three surfaces, a base, an apex and 2 processes
The base is concave and articulates with the cricoid cartilage;
The apex articulates with a corniculate cartilage;
Surfaces: medial, anterolateral and Posterior
Vocal process at the anterior angle of the base to which the vocal ligament is
attached.
Muscular process at the lateral angle of the base
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• Corniculate cartilages:
Two
small
conicalshaped
cartilages
articulate
with
the
arytenoid
cartilages
They give attachment to
the aryepiglottic folds.
• Cuneiform cartilages:
These two small rodshaped cartilages are
found in the aryepiglottic
folds and serve to
strengthen them
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Joints of the larynx
• Crico-thyroid joint is a synovial joint between inferior
cornu of thyroid cartilage and a facet on the base of
cricoid cartilage; in this joint movement is possible
around transversal axis;
• Crico-arytenoid joint is a synovial joint between base
of arytenoid cartilages and a facet on the superolateral
border of the lamina of cricoid cartilage. Arytenoid
cartilage can rotate slide to meet one another.
• Arycorniculate joints is a cartilagenous joint between
the apex of arytenoid cartilage and the corniculate
cartilage.
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Membranes and ligaments of the larynx
• Thyro-hyoid membrane
• Cricotracheal ligament
• Crico-thyroid ligament
•Quadrangular membrane
Fibroelastic membranes
together with laryngeal
cartilages
form
a
laryngeal skeleton.
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Thyrohyoid membrane
it connects the upper margin of
the thyroid cartilage to the
hyoid bone.
In the midline it is thickened to
form the median thyrohyoid
ligament.
Its lateral margin also thickened
to
form
the
lateral
thyrohyoid ligament
The membrane is pierced on
each side by the superior
laryngeal vessels and the
internal laryngeal nerve, a
branch
of
the
superior
laryngeal nerve
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Cricothyroid ligament
The cricothyroid ligament is attached to the
arch of cricoid cartilage and extends
superiorly to end in a free upper margin which
is composed of elastic tissue .
On each side, this upper free margin attaches:
Anteriorly to the inner surface of
cartilage at its angle.
thyroid
Posteriorly to the vocal processes of the
arytenoid cartilages.
The free margin between these two points of
attachment is thickened to form the vocal
ligament on each side. The vocal
ligaments form the interior of the vocal
folds (vocal cords).
The cricothyroid ligament is also thickened
anteriorly in the midline to form a distinct
median cricothyroid ligament.
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Epiglotti
s
Thyrohyoid
membrane
Cuneiform
cartilage
Corniculate
cartilage
Arytenoid
cartilage
Arytenoid
muscles
Cricoid
cartilage
Tracheal cartilages
Body of hyoid
bone
Thyrohyoid
membrane
Fatty
pad
Vestibular fold
(false vocal
cord)
Thyroid
cartilage
Vocal fold
(true vocal
cord)
Cricothyroid
ligament
Cricotracheal
ligament
(b) Sagittal view; anterior surface to the right
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Quadrangular membrane
The quadrangular membrane on each
side runs between the lateral margin
of the epiglottis and the anterolateral
surface of the arytenoid cartilage on
the same side.
Each quadrangular membrane has a
free upper margin and a free lower
margin.
Its inferior margin thickened
forms the vestibular ligament,
to
the vestibular ligaments form the
interior of the vestibular folds
On each side, the vestibular ligament
is separated from the vocal ligament
below by a gap (rima glottidis).
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Cricotracheal
ligament : connects
the cricoid cartilage to
the first ring of the
trachea
Hyo-epiglottic
ligament
It
extends from the
midline of the epiglottis
to the body of the hyoid
bone
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Laryngeal Folds
Vestibular Fold
The vestibular fold is a fixed fold on
each side of the larynx It is formed
by mucous membrane covering the
vestibular ligament
It is vascular and pink in color.
Vocal Fold (Vocal Cord)
The vocal fold is a mobile fold on
each side of the larynx and is
concerned with voice production.
It is formed by mucous membrane
covering the vocal ligament and is
avascular and white in color.
The vocal fold moves with
respiration and its white color is
easily seen when viewed with a
laryngoscope.
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Rima glottidis (glottis)
The gap between the vocal folds is
called the rima glottidis or glottis.
The glottis is bounded in front by the
vocal folds and behind by the
medial surface of the arytenoid
cartilages.
So it divides into intermembrenous
part and intercartilaginous part
The glottis is the narrowest part of
the larynx and measures about 2.5
cm from front to back in the male
adult and less in the female.
In children the lower part of the
larynx within the cricoid cartilage is
the narrowest part.
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Inlet of the Larynx
The inlet of the larynx looks backward and upward
into the laryngeal part of the pharynx
The opening is wider in front than behind
Boundaries of the inlet
in front; the epiglottis,
On each side; the aryepiglottic fold of mucous
membrane.
Posteriorly; the arytenoid
corniculate cartilages.
cartilages
with
the
The cuneiform cartilage lies within and strengthens the
aryepiglottic fold.
The piriform fossa is a recess on either side of inlet
It is bounded;
Medially by the aryepiglottic fold
Laterally by the thyroid cartilage and the thyrohyoid
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Cavity of the Larynx
The cavity of the larynx extends from the inlet to the lower
border of the cricoid cartilage. It is divided into three regions:
1. The vestibule, which is situated between the inlet and the
vestibular folds
2. The middle region, which is situated between the vestibular
folds above and the vocal folds below
3. The lower region, which is situated between the vocal folds
above and the lower border of the cricoid cartilage below
Sinus of the Larynx is a small recess on each side of the
larynx situated between the vestibular and vocal folds. It is
lined with mucous membrane.
Saccule of the Larynx is a diverticulum of mucous membrane
that ascends from the sinus. The mucous secretion lubricates
the vocal cords
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Muscles of the Larynx
The muscles of the larynx may be divided into two groups:
extrinsic and intrinsic muscles.
Extrinsic muscle
These muscles move the larynx up and down during swallowing.
Note that many of these muscles are attached to the hyoid
bone, which is attached to the thyroid cartilage by the thyrohyoid
membrane. It follows that movements of the hyoid bone are
accompanied by movements of the larynx.
Elevation: The digastric, the stylohyoid, the mylohyoid, the
geniohyoid, the stylopharyngeus, the salpingopharyngeus, and
the palatopharyngeus muscles
Depression: The sternothyroid, the sternohyoid, and the
omohyoid muscles
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Intrinsic muscles of the larynx
Five muscles move the vocal folds (cords).
•
Tensing the vocal cords: The cricothyroid muscle
•
Relaxing the vocal cords: The thyroarytenoid (vocalis) muscle
•
Adducting the vocal cords: The lateral cricoarytenoid muscle
•
Abducting the vocal cords: The posterior cricoarytenoid
muscle
•
Approximates the
arytenoid muscle
arytenoid
cartilages:
The
Two muscles modify the laryngeal inlet
•
Narrowing the inlet: The oblique arytenoid muscle
•
Widening the inlet: The thyroepiglottic muscle
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transverse
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Cricothyroid Muscle
Origin; anterolateral aspect of
arch of cricoid cartilage
Insertion; lower border and
inferior cornu of thyroid cartilage
Innervation; external branch of
superior laryngeal nerve from the
vagus nerve
Action; it pull the thyroid cartilage
forward and rotate it down
relative to the cricoid cartilage.
This action tenses vocal cords .
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Thyro-arytenoid (Vocalis)
• Origin; thyroid angle
(Inner surface of
thyroid cartilage)
• Insertion;
anterolateral surface
of arytenoid cartilage
• Nerve supply;
recurrent laryngeal
branch of the vagus
nerve
• Action; relaxes vocal
cords
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• Lateral cricoarytenoid
Origin: Superior border of arch of cricoid
cartilage
Insertion: Anterior surface of muscular
process of arytenoid cartilage
Nerve supply: recurrent laryngeal nerve
Action: Adduction and internal rotation of
the arytenoid cartilage
Posterior cricoarytenoid
Origin: posterior surface of lamina of
cricoid cartilage
Insertion: Posterior surface of muscular
process of arytenoid cartilage
Nerve supply: recurrent laryngeal nerve
Action: external rotation and abduction
of the arytenoid cartilage
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ACTION OF THE POSTERIOR
CRICOARYTENOID MUSCLES
Adduction of Vocal Folds
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ACTION OF THE LATERAL
CRICOARYTENOID MUSCLES
Adduction of Vocal Folds
Transverse arytenoid
Origin Back and medial surface of arytenoid
cartilage
Insertion Back and medial surface of
opposite arytenoid cartilage
Nerve supply Recurrent laryngeal branch of
the vagus nerve
Action Adduction of arytenoid cartilages
Oblique arytenoid
Origin
Posterior surface of muscular
process of arytenoid cartilage
Insertion Posterior surface of apex of
adjacent arytenoid cartilage; extends into
aryepiglottic fold
Nerve supply Recurrent laryngeal branch
of the vagus nerve
Action; Narrows the inlet by bringing the
aryepiglottic folds together
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Thyroepiglottic muscle
Origin; Medial surface of
thyroid cartilage
Insertion; Lateral margin
of epiglottis and
aryepiglottic fold
Nerve supply; Recurrent
laryngeal nerve
Action; Widens the inlet
by pulling the aryepiglottic
folds apart
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Movements of the Vocal Folds With Respiration
•
On quiet inspiration, the vocal folds are
abducted and the rima glottidis is
triangular in shape with the apex in
front
•
On deep inspiration, the vocal folds are
maximally abducted and the glottis
becomes a diamond shape because of
the maximal lateral rotation of the
arytenoid cartilages
•
On expiration the vocal folds are
adducted, leaving a small gap between
them
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Sphincteric Function of the Larynx
• There are two sphincters in the larynx: one at the
inlet and another at the rima glottidis.
• The sphincter at the inlet is used only during
swallowing. The inlet of the larynx is narrowed by
the action of the oblique arytenoid and
aryepiglottic muscles.
• The rima glottidis acts as a sphincter
1. In coughing or sneezing
2. To increase the intra-abdominal pressure
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The major blood supply to the larynx
•
The major blood supply to the larynx
•
The superior laryngeal artery originates from the superior thyroid
artery, and accompanies the internal branch of the superior laryngeal
nerve through the thyrohyoid membrane to reach the larynx.
•
The inferior laryngeal artery originates from the inferior thyroid
artery, together with the recurrent laryngeal nerve, ascends in the
groove between the esophagus and trachea. It enters the larynx by
passing deep to the margin of the inferior constrictor muscle of the
pharynx
•
Veins
•
superior laryngeal veins drain into superior thyroid veins, which in
turn drain into the internal jugular veins .
•
inferior laryngeal veins drain into inferior thyroid veins, which drain
into the left brachiocephalic veins.
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Lymphatic drainage of larynx
Above the vocal cords
the larynx drains to the
upper deep cervical
and to the mediastinal
lymph nodes
Below
the
cords,
drainage is to the lower
deep cervical nodes,
partially via nodes on
the front of the larynx
and trachea.
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Nerve supply
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