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2. INTRODUCTION
The oral apparatus is the ‘gateway to the gut’. It
is in unbroken continuity with the pharynx, which
funnels directly into the oesophagus. The
structure of this food channel is complicated by
the peculiar crossing of the air way at the larynx.
Since the oral apparatus not only prepares food
but also initiates swallowing, it is designed to
function in close co-ordination with the pharynx.
Further more the oropharyngeal system is tightly
integrated with the production of speech.
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3. The oropharyngeal system consists of
the following parts.
1. Soft Palate
2. Pharynx
a. Nasopharynx
b. Oropharynx
c. Laryngopharynx
3. Larynx
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4. SOFT PALATE
• It is a movable muscular fold suspended from
the posterior border of the hard palate and fused
at the sides with the lateral wall of the pharynx.
• It is covered with stratified squamous
epithelium on its oral surface and the posterior
part of its nasal surface. The anterior part of the
nasal surface is covered with respiratory mucous
membrane. The thickness of the palate and
uvula is occupied by a large mass of mucous
and serous glands.
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6. The soft palate consists of an aponeurosis
that is acted upon by five pairs of
muscles to alter its shape and function.
They are
• Tensor veli palatini
• Levator Veli palatini
• Musculus Uvulae
• Palatoglossus
• Palatopharyngeus.
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7. 1. Tensor Veli Palatini: This is a thin,
triangular muscle
• origin
– Lateral side of auditory tube.
– Greater wing and Scaphoid fossa of the
sphenoid bone.
• Insertion
Muscle discards, converges to form a
delicate tendon which winds round the
pterygoid hamulus, passes through the
origin of buccinator and flattens out to
form the palatine aponeurosis.
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8. Aponueurosis is attached to
• Posterior border of hard palate.
• Inferior surface of hold palate behind
palatine crest.
Actions
• Tightens the soft palate, chiefly the anterior
post.
• Opens the auditory tube to equalize the air
pressure between the middle ear and nose.
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9. 2. Levator Veli Palatini.
• This is a cylindrical muscle that lies deep to the
tensor Veli palatini.
Origin
• Inferior aspect of auditory tube.
• Adjoining part of the inferior surface of petrous temporal
bone.
Insertion
• Muscle enters the pharynx by passing over the upper
concave margin of the superior constrictor runs
downwards and medially and spreads out in the soft
palate and insects into the upper surface of palatine
aponeurosis.
Actions
• Elevates soft palate and closes the pharyngeal isthmus.
• Opens the auditory tube, like tensor palati.
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10. 3. Musculus Uvulae.
This is a longitudinal strip of muscle
placed on one side of the modern plane,
within the palatine aponeurosis.
Origin a. Posterior nasal spine.
b. Palatine aponeurosis.
Insertion
Mucous membrane of Uvula.
Action
Pulls up the Uvula.
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11. 4. Palatoglossus
Origin
Oral surface of the palatine aponeurosis
Insertion
Descends in the palatoglossal arch, to the
side of the tongue at the junction of its oral and
pharyngeal parts.
Action:
Pulls up the loot of the tongue, approximates
the palatoglossal arches and thus closes the
oropharyngeal isthmus.
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12. 5. Palatopharyngeus
• It consists of two fasciculi (Heads), that ale separated
by the levator palati.
Origin
• Anterior fasciculus: from posterior border of hard
palate.
• Posterior fasciculus: from palatine aponeurosis.
Path and Insertion
• It descends in the palatopharyngeal arch and spreads
out to form the greater poet of the longitudinal muscle
coat of the pharynx. It is inserted into
• Posterior border of the lamina of the thyroid cartilage.
• Wall of the pharynx and its median raphae.
Action
• Pulls up the wall of the pharynx and shortens it during
swallowing.
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13. Passavants Ridge
Some of the upper fibres of the
palatopharyngeus pass circulating deep to
the mucous membrane of the pharynx,
and form a sphincter internal to the
superior constrictor. These fibres
constitute Passavants muscle which on
contraction raises a ridge (Passavants
ridge) on the posterior wall of the
nasopharynx. When soft palate is
elevated it comes in contact with this ridge
closing the pharyngeal isthmus.
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14. NERVE SUPPLY
Motor
• All muscles of soft palate except Tensor
palati are supplied by pharyngeal plexus
(accessory nerve). Tensor Palati supplied by
mandibular nerve.
General sensory
• Lesser palatine nerve (maxillary nerve)
• Glossopharyngeal nerve.
Special Sensory (Gustatory)
• Lesser palatine nerve.
Secretomotors
• Lesser palatine nerve.
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15. BLOOD SUPPLY
Arterial
• Greater palatine branch of maxillary
artery.
• Ascending palatine branch of facial artery.
• Palatine branch of ascending pharyngeal
artery.
Venous
• To the pterygoid and tonsillar plexus of
veins.
Lymphatics
• It drains into the upper deep cervical
and retro pharyngeal Lymph nodes.
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16. FUNCTIONS OF SOFT PALATE
• The palate controls two gates, the pharyngeal
isthmus and oropharyngeal isthmus. It can
completely close them, or can regulate their size
according to requirements. Through these
movements the soft palate plays an important role
in chewing, swallowing speech, coughing, sneezing
etc. A few specific roles are
• It isolates the mouth from the oropharynx during,
so that breathing is unaffected.
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17. • It severities the oropharynx from the
nasopharynx by locking into passavants ridge
during swallowing, so that food does not enter
the nose.
• By varying degree of closure of pharyngeal
isthmus, the quality of voice can be modified and
various consonants correctly pronounced.
• During sneezing, the blast of air is appropriately
divided and directed through the nasal and oral
cavities without damaging the narrow nose.
Similarly during coughing it directs air and
sputum into the mouth and not nose.
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18. Applied Anatomy
Palatophayryngeal incompetance may occur due to
muscle hypoplasia, particularly of the musculus
uvulae. Submucous clefts resulting from this may be
revealed clinically as a ‘V’ shaped notch in the
midline of the soft palate during function.
Paralysis of the soft palate may follow diphtheria
due to action of the toxin on the nerve cells of the
medulla. In this state voice becomes nasal and fluids
regurgitate into the nose during swallowing.
Other pathological processes involving
glossopharyngeal, vagus, accessory nerves or their
nuclei in the medulla also cause palatal paralysis.www.indiandentalacademy.com
19. PHARYNX
The pharynx is a wide muscular tube, situated
behind the nose, mouth and the larynx. Its roof is
situated immediately below the cranial base, its
inferior end continues into the Oesophagus. Its
posterior wall lies immediately in front of the
vertebral bodies. It lateral walls converge downward.
The anterior wall is incomplete because through it,
the nasal cavities open into the upper part and the
oral cavity into the middle part of the pharynx.
Whereas from the lower part of the pharynx the
entrance into the larynx is accessible. According to
the communication with the three cavities the
pharynx is arbitrarily divided into a nasal, an oral
and a laryngeal part. The length of the pharynx is
about 12 cm. The upper part is widest and narrows
as it proceeds towards giving it a funnel shape.www.indiandentalacademy.com
21. NASOPHARYNX.
• This is the upper part of the pharynx situated
behind the nose and above the lower border of
the soft palate.
• In each lateral wall of the Nasopharynx there
is an opening which leads into the auditory
tube. This tube connects the Nasopharynx to
the middle ear. The cartilage of the tube bulges
out into the pharyngeal cavity. This bulge, called
tubal elevation or tubal torus flanks the opening
of the tube on its upper and posterior
circumference. From the anterior end of this
elevation as small fold, the salpingopalatine fold
extends to the soft of soft palate.
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22. • A much more prominent and sharper fold arises
from the posterior end of the tubal torus and
continues downward on the lateral wall of the
pharynx itself. This fold, the salpingopharyngeal
fold, contains the salpingo pharyngeal muscle.
Behind the tubal elevation the wall for the
nasopharynx shows depression called the
pharyngeal or Rosenmuller’s recess.
• The mucosa of the median part of the roof
shows a bulging produced by a mass of
lymphoid tissue called pharyngeal tonsil. Some
lymphoid tissue is also present behind the
auditory tube which is called tubal tonsil.
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23. OROPHARYNX.
• This is the middle part of the pharynx situated
behind the oral cavity. Above it communicates with
the nasopharynx through the pharyngeal isthmus.
Infant it communicates with the oral cavity through
the oropharyngeal isthmus. Below it opens into the
laryngopharynx at the level of the upper border of
epiglottis. Behind it is supported by the body of the
axis vertebra upper part of the body of the third
cervical vertebra. Its lateral wall presents the
palatine tonsil which lies in the tonsillar fossa. This
fossa is bounded anteriorly by the palatoglossal
arch, and posteriorly by the palatapharyngeal arch.
The palatopharyngeal fold extends down wards and
slightly backwards over the entire height of
oropharynx. The fold is elevated by the
palatopharyngeal muscle. The posterior wall of the
oropharynx is formed by the three constrictors of the
pharynx. www.indiandentalacademy.com
24. Laryngopharynx
• This is the lower part of the pharynx situated
behind the larynx. It extends from the upper
border of the epiglottis to the lower border of the
cricoid cartilage (C6 Vertebra), where it
becomes continuous with the oesophagus. The
anterior wall presents the inlet of larynx and the
posterior surfaces of cricoid and arytenoid
cartilages.
• The posterior wall is supported mainly by the
4th and 5th cervical vertebra and partly by 3rd
and 6th vertebra. In this region the posterior
wall of the pharynx is formed by the superior,
middle and inferior constrictor of pharynx.
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25. The lateral wall presents a depression
called the piriform recess or form, one on
each side of the inlet of the larynx,
between the aryepiglottis fold and the
lateral pharyngeal wall. An oblique field in
the piriform recess, called Hyrtl’s fold
owes its existence to the internal branch of
the superior laryngeal nerve. Below the
piriform recess and the laryngeal
prominence the pharyngeal space
narrows rather abruptly and continues into
the oesophagus.
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26. Pharyngobasilar fascia (Pharyngeal aponeurosis)
• This is a fibrous sheet internal to the pharyngeal
muscles. It is thickest in the upper part where it fills
the gap between upper border of the superior
constrictor and the base of the skull and also
posteriorly while it forms the pharyngeal raphae.
• 4. The muscular coat consists of an outer circular
layer mode up of the three constrictors, and an inner
longitudinal layer mode up of stylopharyngeus, the
salplingopharyngeus and the palatopharynegus
muscles.
• 5. The buccopharyngeal fascia covers the outer
surface of the constrictors of the pharynx and extends
forwards across the pterygomandibular raphae to
cover the buccinator. Between the buccopharyngeal
fascia and the muscular coat there are the pharyngeal
plexus of veins and nerves.
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29. MUSCLES OF THE PHARYNX.
Constrictors
• The muscular basis of the wall of the pharynx
is formed mainly by the three pairs of
constrictors.
Origin
The superior constrictor takes origin from the
following:
• Pterygoid hamulus.
• Pterygomandibular raphae.
• Medial surface of the mandible at the posterior
and of the mylohyoid line.
• Side of the posterior part of the tongue.
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30. The middle constrictor takes origin.
• The lower part of the stylohyoid ligament.
• Lesser corner of hyoid bone.
• Upper border of the greater corner of the hyoid
bone
• The inferior constrictor consists of two parts.
The thyropharyngeus and the
cricopharyngeus.
The thyropharyngeus arises from
• The oblique line on the lamina of the thyroid
cartilage, including the inferior tubercle.
• A tendinous band that crosses the cricothyroid
muscle.
• The inferior corner of the thyroid cartilage.
The cricopharyngeus arises from the cricoid
cartilage behind the origin of the cricothyroid
muscle. www.indiandentalacademy.com
31. Insertion
All the constrictor of the pharynx are inserted
into a median raphae on the posterior wall of the
base of the skull while it is attached to the
pharyngeal tubercle on the basilar part of
occipital bone.
Longitudinal Muscles.
The stylopharyngeus arises from the styloid
process. It passes the gap between superior
and middle constrictors to run down wards on
the inner surface of middle and inferior
constrictors and is inserted into the posterior
of the thyroid lamina and the side wall of the
pharynx.
The salpingopharyngeus a very slender
muscle that arises from the lower part of the
cartilage of the auditory tube and runs
downwards to blend with the palatopharynx –
palatopharyngeus.www.indiandentalacademy.com
33. Nerve Supply
Motor supply of the pharynx is by the pharyngeal
plexus.
The plexus is formed by
i. Pharyngeal branch of vagus
ii. Pharyngeal branches of glosspharyngeal
nerve
iii. Pharyngeal branches of superior cervical
sympathetic ganglion) extent stylopharyngeus
which is supplied by the glossopharyngeal
nerve.
The inferior constrictor (Cricopharyngeus) may
receive an additional supply from external and
recurrent laryngeal nerves.
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35. BLOOD SUPPLY
Arterial supply
• Ascending pharyngeal branch of external
carotid artery.
• Ascending palatine and tonsilor branches of
facial artery.
• Dorsal lingual branches of the lingual artery.
• Greater palatine, pharyngeal and pterygoid
branches of maxillary artery.
Venous Drainage
• The veins form a plexus (Pharyngeal venous
plexus) on the postero lateral aspect of
pharynx. The plexus receives blood from
pharynx, soft palate and the prevertebral
region. It drains into the internal jugular and
facial veins. www.indiandentalacademy.com
36. Lymphatic Drainage
Lymph from the pharynx drains into the
retro pharyngeal and deep cervical lymph
nodes.
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37. Applied Anatomy
Dysphagia due to paralysis of muscles of
pharynx is produced by lesions of the vagus
nerve.
Pharyngeal diverticulum may form due to
incoordination between two parts of the
inferior constrictor.
Inflammation of the auditory tube secondary
to an attack of common cold or sore throat is
common occurrence. This causes pain in the
ear aggravated by swallowing, due to
blockage of the tube. This is relieved by
decongestant drops in the nose.
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38. LARYNX
The larynx is the organ for production of voice
(Phonation). It is also an air passage, and acts
as a sphincter at the inlet of the lower respiratory
passages. (The upper respiratory passages
include the nose, the nasopharynx and the
oropharynx).
Situation and extent.
The larynx lies in the anterior midline of the
neck, extending from the root of the tongue to
the trachea. In the adult male it lies front of the
3rd, 4th, 5th and 6th cervical vertebrae, but in
children and in the adult female it lies at a high
level.
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39. Size.
The length of the larynx is 44 mm in male and
36 mm in females. Until puberty the size is
more or less same in the two sexes, but at
puberty the male pharynx grows rapidly and
becomes larger than the female larynx. The
pubertal growth of the female larynx is
negligible.
Constitution of Larynx.
The larynx is made up of a skeletal framework of
cartilages. The cartilages are connected by
joints, ligaments and membranes; and the
moved by a number of muscles. The cavity of
the larynx is lined by mucous membrane.www.indiandentalacademy.com
40. THE SKELETON (CARTILAGES) OF LARYNX
The larynx contains 9 cartilages, of which 3 are
unpaired and 3 are paired.
Unpaired cartilages
• Thyroid
• Cricoid
• Epiglottis
Paired cartilages
• Arytenoid
• Corniculate
• Cuneiform.
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41. Thyroid Cartilage
This cartilage is V-shaped in cross section.
It consists of right and left laminae. Each lamina
is roughly quadrilateral. The laminae are
placed obliquely relative to the midline; their
posterior borders are far apart, but the anterior
borders approach each other at an angle that is
about 90 degrees in the male and about 120
degrees in the female. The lower parts of the
anterior borders of the right and left laminae fuse
and form a median projection called the
laryngeal prominence. The upper parts of the
anterior borders do not meet.www.indiandentalacademy.com
42. They are separated by the thyroid notch. The
posterior borders are free. They are prolonged
upwards and downwards as the superior and
inferior cornua (horns). The superior cornu is
connected with the greater cornu of the hyoid
bone by the lateral thyrohyoid ligament (in which
a small cartilago tritica may develop).
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43. The inferior cornu articulates with the cricoid
cartilage to form the cricothyroid joint. The
superior border of the thyroid cartilage is convex
in front and concave behind. In the median
plane it is connected to the cricoid cartilage by
the conus elasticus. The outer surface of each
lamina is marked by an oblique line which
extends from the superior thyroid tubercle (in
front of the root of the superior cornu) to the
inferior thyroid tubercle (behind the middle of the
inferior border). The thyrohyoid and the inferior
constrictor of the pharynx are attached to the
oblique line.
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44. Cricoid Cartilage
This cartilage is shaped like a ring. It
encircles the larynx below the thyroid cartilage.
It is thicker and stronger than the thyroid
cartilage. The ring has a narrow anterior part
called the arch, and a broad posterior part,
called the lamina. The lamina projects upwards
behind the thyroid cartilage, and articulates
superiorly with the arytenoids cartilages. The
inferior cornu of the thyroid cartilage articulates
with the side of the cricoid cartilage at the
junction of the arch and lamina.
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45. Epiglottic Cartilage
This is a leaf shaped cartilage placed in the
anterior wall of the upper part of the larynx. Its
upper end is broad and free, and projects upwards
behind the hyoid bone and the tongue. The lower
end (Stalk) is pointed and is attached to the upper
part of the angle between the two laminae of the
thyroid cartilage. The right and left margins of the
cartilage provide attachment to the aryepiglottic
folds. Its anterior surface is connected
– To the tongue by a median glossoepiglottic fold
and
– To the hyoid bone by the hyoepiglottic ligament.
The posterior surface is covered with mucous
membrane, and presents a tubercle in the lower
part.
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46. Arytenoid Cartilages
These are two small pyramid shaped
cartilages lying on the upper border of the
lamina of the cricoid cartilage. The apex of the
arytenoids cartilage is curved posteromedially
and articulates with the corniculate cartilage. Its
base is concave and articulates with the lateral
part of the upper border of the cricoid lamina. It
is prolonged anteriorly to form the vocal process,
and laterally to form the muscular process. The
surface of the cartilage is anterolateral, medial
and posterior.
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47. Corniculate cartilage
• These are two small conical nodules
which articulate with the apex of the
arytenoids cartilages, and are directed
posteromedially. They lie in the posterior
parts of the aryepiglottic folds.
Cuneiform Cartilages.
• These are two small rod shaped pieces
of cartilage placed in the aryepiglottic folds
just ventral to the corniculate cartilages.
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50. Histology of Laryngeal Cartilage.
• The thyroid and cricoid cartilages, and the
basal parts of the arytenoids cartilages are
made up of hyaline cartilage. They may ossify
after the age of 25 years. The other cartilages of
the larynx are made of elastic cartilage, and do
not ossify.
LARYNGEAL JOINTS
• The cricothyroid joint is a synovial joint
between the inferior cornu of the thyroid
cartilage and the side of the cricoid cartilage. It
permits rotatory movements around a transverse
axis, and also gliding movements in different
directions.
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51. • The cricoarytenoid joint is also a synovial joint between
the base of the arytenoids cartilage and the upper
border of the lamina of the cricoid cartilage. It permits
rotatory movements around a vertical axis, and also
gliding movements in all directions.
LARYNGEAL LIGAMENTS AND MEMBRANES
Extrinsic
• The thyrohyoid membrane connects the thyroid
cartilage to the hyoid bone. Its median and lateral
parts are thickened to form the median and lateral
thyrohyoid ligaments. The membrane is pierced by the
internal laryngeal nerves, and by the superior laryngeal
vessels.
• The hyoepiglottic ligament connects the lower end of
the epiglottic cartilage to the hyoid bone.
• The cricotracheal ligament connects the cricoid
cartilages to the upper end of the trachea.www.indiandentalacademy.com
52. Intrinsic
• The intrinsic ligaments are part of a broad sheet of
fibroelastic tissue, known as the fibroelastic membrane
of the larynx. This membrane is placed just outside the
mucous membrane is placed just outside the mucous
membrane. It is interrupted on each side by the sinus of
the larynx. The part of the membrane above the sinus is
known as the quadrate membrane, and the part below
the sinus is called the conus elasticus.
• The quadrate membrane extends from the
arytenoids cartilage to the epiglottis. It has a lower free
border which forms the vestibular fold; and an upper
border which forms the aryepiglottic fold.
• The conus elasticus (or cricovocal membrane)
extends upwards and medially from the arch of the
cricoid cartilage. The anterior part is thick and is known
as the cricothyroid ligament. The upper free border of
the conus elasticus forms of vocal cord.www.indiandentalacademy.com
53. Cavity of Larynx
• The cavity of the larynx extends from the inlet of the larynx to
the lower border of the cricoid cartilage. The inlet of the
larynx is placed obliquely. It looks backwards and upwards,
and opens into the laryngopharynx. The inlet is bounded
anteriorly by the epiglottis; posteriorly by the inter arytenoids
fold of mucous membrane; and on each side by the
aryepiglottic fold.
• Within the cavity of larynx, there are two folds of mucous
membrane on each side. The upper fold is the vestibular
fold, and the lower fold is vocal fold. The space between the
right and lest vestibular folds is the rima vetibuli; and the
space between the vocal folds is the rima glottidis. The vocal
is attached anteriorly to the middle of the angle of thyroid
cartilage (on its posterior aspect); and posteriorly to the vocal
process of the arytenoids cartilage. The rima glottides is
limited posteriorly by an inter arytenoids fold of mucous
membrane. The rima therefore has an anterior
intermembranous part (3/5) and a posterior intercartilaginous
part. The rima is the narrowest part of the larynx. It is longer
(23 mm) in males than in females (17mm).www.indiandentalacademy.com
54. The vestibular and vocal folds divide the cavity of the
larynx into three parts
– The part above the vestibular fold is called the
vestibule of the pharynx.
– The part between the vestibular and vocal folds is
called the sinus (or ventricle) of the larynx.
– The part below the vocal folds is called the infra
glottic part.
The sinus or ventricle of the pharynx is a narrow
fusiform cleft between the vestibular and vocal folds.
The anterior part of the sinus is prolonged upward as a
diverticulum between the vestibular fold and the lamina
of the thyroid cartilage. This extension is known as
the saccule of the larynx. The saccule contains
mucous glands which help to lubricate the vocal folds.
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55. Mucous Membrane of Larynx.
• The anterior surface and upper half of the posterior
surface of the epiglottis, the upper parts of
aryepiglottic, the upper parts of aryepiglottic folds, and
the vocal folds are lined by stratified squamous
epithelium. The rest of the laryngeal mucous
membrane is covered with ciliated columnar
epithelium.
• the mucous membrane is loosely attached to the
cartilage of the larynx except over the vocal ligaments
and over the posterior surface of the epiglottis where
it is thin and firmly adherent.
• Mucous glands are absent over the vocal cords, but
are plentiful over the anterior surface of the epiglottis,
around the cuneiform cartilages and in the vestibular
folds. The glands are scattered over the rest of the
larynx.
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56. INTRINSIC MUSCLES OF LARYNX
• These are as follows
Cricothyroid
• This is the only intrinsic muscle lying on the external
aspect of the larynx.
Origin
• Lower border and lateral surface of the cricoid cartilage.
Insertion
• Its fibres pass backwards and upwards to be inserted into
the inferior cornu and lower border of the thyroid cartilage.
Posterior Cricoarytenoid
• This is a triangular muscle.
Origin
• Posterior surface of the lamina of the cricoid cartilage.
Insertion
• Its fibres pass upwards and laterally and are inserted into
muscular processes of the arytenoids cartilage.
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57. Lateral Cricoarytenoid
Origin
• Lateral part of the upper border of the arch of
the cricoid cartilage.
Insertion
• Its fibres pass upwards and backwards to be
inserted into the muscular process of the
arytenoids cartilage.
Transverse arytenoids
• This is the only unpaired intrinsic muscle of
the larynx. Its fibres run transversely from the
posterior surface of one arytenoids cartilage to
that of the opposite arytenoids cartilage.
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58. Oblique Arytenoid
These are slips of muscle that run obliquely across the midline crossing
each other. Each slip arises from the muscular process of one arytenoids
cartilage and is inserted into the apex of the opposite arytenoids cartilage.
Aryepiglotticus
This is made up of some fibres of the oblique arytenoids which are
continued into the aryepiglottic fold to reach the edge of the epiglottic
cartilage.
Thyroarytenoid
Origin
From the posterior aspect of the single of the thyroid cartilage and the
adjacent part of the cricothyroid ligament.
Insertion
The fibres run backwards and upwards to reach the anterolateral surface of
the arytenoids cartilage.
Vocalis
The vocalis is made up of some fibres of the thyroarytenoid that gain
attachment to the vocal ligament.
Thyroepiglotticus.
Some of the upper fibres of the thyroarytenoid curve upwards into the
aryepiglottic fold to reach the edge of the epiglottis. These constitute the
thyroepiglotticus.
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60. Nerve supply of Muscles.
All intrinsic muscles of the larynx are supplied by the
recurrent laryngeal nerve except for the cricothyroid which
is supplied by the external laryngeal nerve.
Action
Muscles which open the glottis- posterior cricoarytenoids.
Muscles which close the glottis.
– Lateral cricoarytenoids.
– Transverse arytenoids.
– Cricothyroids and
– Thyroarytenoids.
Muscles which tense the vocal cords- cricothyroids.
Muscles which relax the vocal cords
– Thyroarytenoids and
– Vocalis.
Muscles which close the inlet of the larynx.
– Oblique arytenoids
– Aryepiglottics.
Muscles which open the inlet of larynx; Thyroepiglotticuswww.indiandentalacademy.com
61. Arterial supply and Venous Drainage of Larynx.
•Up to the vocal folds: by the superior laryngeal artery, a
branch of the superior thyroid artery. The superior
laryngeal vein drains into the superior thyroid vein.
•Below the vocal folds. By the inferior laryngeal artery, a
branch of the inferior thyroid artery. The inferior laryngeal
vein drains into the inferior thyroid vein.
Lymphatic drainage
Lymphatics from the part above the vocal folds drain
along the superior thyroid vessels to the anterosuperior
group of deep cervical nodes.
Those from the part below the vocal folds drain to the
posterioinferior group of deep cervical nodes. A few of
them drain through the pre-laryngeal nodes.
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62. Nerve supply of Larynx.
• Motor nerves- same as nerve supply of the
muscles.
• Sensory nerves. The internal laryngeal nerve
supplies the mucous membrane above the level
of the vocal folds. The recurrent laryngeal nerve
supplies it below the level of the vocal folds.
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63. Applied Anatomy
Damage to the internal laryngeal nerve
produces anesthesia in the supraglotic part of
larynx, so that foreign bodies can readily enter.
Damage to external laryngeal nerve causes
some weakness of phonation.
Damage to both recurrent laryngeal nerve leads
to loss of phonation completely, breathing
becomes difficult.
Since larynx is the narrowest part of the
respiratory passage, foreign bodies are usually
lodged here.
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64. MECHANISMS OF THE SYSTEM
The human oral apparatus is a special complex
built to perform two crucial functions, one of which
is peculiar to man. It is a food processing device in
feeding and a major part of a sound processing
device in the specific form of communication called
speech.
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65. Swallowing
For feeding, three essential features have been incorporated into
local design; an input device, a processing mechanism, and an output
device. Thus three separate performances can be distinguished in
normal feeding; movements of taking food into the mouth, movements for
the preparation of the bolus, and movements of swallowing. These
activities are so integrated, however, as to overlap within the oral cavity.
Movements for taking food into the mouth depend on the consistency of
the food. Liquids are brought in by sucking, which is separable into
infantile suckling and adult drinking. Solids are pulled in by plucking from
fingers or feeding utensils. Since little preparation is needed for the
passing of liquids and solids are different. Swallowing activities for
liquids and solids also show differences and swallowing behavior is
further influenced by the size of the bolus. The conspicuous feature of
the entire swallowing system is the extra ordinary crossing of air and food
channels. Around this critical location precisely timed valvular devices
have been installed. www.indiandentalacademy.com