ANATOMY OF LARYNX

ANATOMY OF
LARYNX
BY SURAJ DHARA (MMCH)

INTRODUCTION
 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.

DEVELOPMENT OF LARYNX
 Development of larynx
occur during the 4th
week of intra uterine life
 The respiratory
primordium appears in
the floor of the foregut
in the 4th week of
gestational life.
 The larynx begins as a
slit like
diverticulum(laryngotrac
heal groove ) in the
ventral wall of the
primitive pharynx .

 The groove gradually
deepens and its edges
fuse to form a septum,
 this septum separates
the laryngotracheal
tube from the pharynx
and oesophagus.
 The process of this
fusion starts caudally
and extend cranially

 Between 5th & 6th weeks,
— 3 swellings
appear at the laryngeal
aditus.
 An anterior swelling , a
derivative of the
hypobranchial eminence
from 4th arch—forms
Epiglottis.
 2 lateral arytenoid
swellings appear, derived
from the 6th branchial
arch, move medially and
form a T-shaped aperture

 Laryngeal lumen— temporarily occluded at 8 weeks gestational
age as a result of epithelial proliferation.
 By the 10th week of gestation, recanalization occurs and
consequently pair of laryngeal ventricles are formed.
 The laryngeal ventricles are bound by mesenchyme tissue that
condense and progress into false and true vocal cords.
 Laryngeal cartilages develop from the mesenchyme of the
branchial arches.
 Thyroid cartilage-- from the 4th arch mesenchyme as two
lateral plates meet in the midline.
 Arytenoids , Corniculate , Cricoid & Tracheal cartilages-- 6th
branchial arch
 Epiglottis — develops from Hypobranchial eminence
 Intrinsic laryngeal muscles develop from the mesoderm of the
4th and 6th arches

EXTERNAL FEATURES OF LARYNX
 Larynx is located anterior to the
3rd, 4th, 5th, and 6th cervical
vertebrae.
 Extends from the base of the
tongue to the proximal portion
of the trachea.
 Laryngeal skeleton is suspended
from the hyoid bone by the
medial and lateral thyrohyoid
membrane.
 The lateral lobes of the thyroid
gland lie anterolateral to the
thyroid and cricoid cartilage.
 Isthmus of the thyroid gland
lies just below the cricoid
cartilage and often covers the
first 1 or 2 tracheal rings.

 The carotid sheath and
its contents lie just
posterolateral to the
larynx.
 The recurrent laryngeal
nerve ascends in the
tracheoesophageal
groove and enters the
larynx just posterior to
the cricothyroid
articulation
 The 3rd to 6th cervical
vertebrae, prevertebral
muscles, and fascia lie
posterior to the larynx.

PRINCIPAL INTERNAL FEATURES OF THE LARYNX
The cavity of the larynx
extends
above – from the area
of the tip of the
epiglottis,aryepiglotti
c folds, and
interarytenoid folds
below — to the 1st
tracheal ring

INTERNAL CAVITY OF THE LARYNX
divided into 3 spaces:
 Supraglottic,
 Glottic, And
 Subglottic spaces

DIFFERENCES BETWEEN ADULT & INFANT
LARYNX
 7 S
1. Size- smaller in infants
2. Shape- funnel shaped in infants , cylindrical in adults
3 . Softness-laryngeal cartilages are softer in infants
4. Superiorly placed in infants
5.Straighter and less oblique than in adults
6.Sensitivity is greater in infants more prone to spasm
7. Sub glottis is very narrow ,even a small swelling can lead
to airway obstruction in infants

Differences between adult & infant Larynx

Average measurements of larynx

SKELITAL ANATOMY
Laryngeal frame work consists of :
 Cartilages
 Joints
 Ligaments
 Membranes
 Muscles
 Mucous membrane
 + Hyoid Bone

HYOID BONE
 Described with the larynx
because of its anatomic
association with the
laryngeal apparatus.
 located in front of the 3rd
cervical vertebra.
 serves as an attachment for
the larynx via the
thyrohyoid membrane and
the extrinsic muscles of
the larynx.
 The hyoid bone is suspended
from the skull base
(temporal bone) via the
stylohyoid ligaments
 It is an U-shaped bone with
 Body
 2 lesser horns (cornua)
 2 greater horns (cornua)

ATTACHMENTS TO THE HYOID BONE
 Medial end of the middle
constrictor muscle and the
stylohyoid ligament attach to the
lesser cornu.
 The middle constrictor and
hyoglossus muscles attach to the
greater cornu.
 geniohyoid and genioglossus
attaches to the inner and upper
surfaces of the body
of the hyoid bone.
 The mylohyoid attaches to the
anterior surface of the hyoid.
 The tendon of the digastric
muscle attaches to the
anterolateral portion of the body.
 sternohyoid, omohyoid, and
thyrohyoid attaches to the
inferior surface of body.
 Each muscle acts to depress the
hyoid bone.

SURGICAL CONSIDERATIONS
 In tracheal resection and anastomosis, a tension-free
closure of the distal airway is essential.
 The larynx can be released and "dropped" from the hyoid
bone to reduce tension on the distal suture line.
 This is accomplished by detaching the infrahyoid muscles
from the inferior surface of the hyoid bone body and
cutting the hyoid bone just lateral to the lesser cornua
 This releases the central body of the hyoid and larynx.
 Additional relaxation can be achieved by cutting the
suspensory ligament of the superior cornu of the thyroid
cartilage
 This can lower the larynx to a maximum of 4.5 cm.
 The hyoid bone serves as a site of access to the
supraglottic larynx and pharynx.

During the excision of a
thyroglossal duct cyst,
 excising the entire
tract along with the
central body of the
hyoid bone (Sistrunk
procedure) reduces the
recurrence rate.

CARTILAGES OF LARYNX :
 3 paired
 3 unpaired
 Paired :
 Arytenoid
 Corniculate
 cunieform
 Unpaired:
 Thyroid
 Cricoid
 Epiglottic

THYROID CARTILAGE
 located anterior to the
4th and 5th cervical
vertebrae.
 formed by 2 laminae which
fuse ventrally in the
midline of the neck,
forming a protuberance,
the laryngeal prominence
or "Adam's apple,―
 The 2 laminae meet at an
angle of 90° in the male
and 120° in the female.
 The upper limit of fusion
of the two laminae forms
the superior thyroid notch

 Posterior border of each lamina
extends upward and downward
as hornlike projections,the
superior and inferior cornua
 The cornua are characterized
further at their origins from
the thyroid laminae by superior
and inferior tubercles.
 Both of the superior horns are
anchored to the tips of the
greater horns of the hyoid
bone;
 both inferior horns articulate
with the cricoid cartilage.
 On the lateral, external surface
of each thyroid lamina is—ridge
,called the oblique line,
 attaches to 3 muscle
1. Sternothyroid,
2. Thyrohyoid,and
3. Thyropharyngeus (a portion of
the inferior pharyngeal
constrictor).

o The thyrohyoid membrane and
median thyrohyoid ligament
are attached to the upper
border of the thyroid
cartilage.
 The lateral thyrohyoid
ligaments attach to the
greater cornua of the thyroid
cartilage.
 The cricothyroid ligaments
(cricothyroid membrane)
attach to the inferior border
of the thyroid cartilage
 5 ligaments attach as one to
the posterior surfaces of the
thyroid laminae near the
union of the laminae (angle):
 The median thyroepiglottic
ligament,
 The 2 vestibular
ligaments,And
 The 2 vocal ligaments.

 The thyroid cartilage is divided in the midline to
expose the endolarynx for various procedures
(for example, partial laryngectomy,
laryngotracheoplasty, and arytenoidectomy).
 The vocalis muscle and vocal ligaments attach to
the inner surface of the thyroid cartilage at the
anterior commissure
 On the external laryngeal surface in adult males
this point is halfway between the thyroid notch
and the inferior border of the thyroid cartilage.
It is slightly higher in adult females.
 In many laryngofissure approaches, it may be
beneficial to stay below the midpoint in order to
avoid dividing the anterior commissure.

CRICOID CARTILAGE
 Shaped like a signet ring.
 signet-shaped portion of the
cricoid faces posteriorly
 the arch is located anteriorly,
 The cricoid cartilage is situated
at vertebral level C6
(occasionally reaching the middle
of C6), just below the thyroid
cartilage
 The cricoid lamina has
 2 superior facets– articulate
with the arytenoid cartilages
and attach to them by the
posterior cricoarytenoid
ligaments
 2 lower lateral facets of the
lamina articulate with the
inferior horns of the thyroid
cartilage.
 The lower border of the cricoid
cartilage is joined to the first
tracheal ring by means of the
thick cricotracheal ligament.

 Arising from the arch of
the cricoid cartilage
anteriorly and externally
are the cricothyroid
muscles.
 The lamina has a midline
ridge for the tendinous
attachment of longitudinal
fibers of the esophagus.
 Lateral to this ridge are
the sites of origin for the
bilateral posterior
cricoarytenoid muscles.

 Injury to the cricoid cartilage from intubation or trauma
may result in perichondritis and lead to subglottic
stenosis.
 Surgical approaches to repair long-standing subglottic
stenosis involve the expansion of the circumference of the
cricoid ring with autologous cartilage grafts.
 Tracheotomies are usually performed at least one tracheal
ring below the cricoid cartilage (2nd or 3rd tracheal ring)
to avoid subglottic stenosis.
 During an emergency cricothyroidotomy, the
tracheostomy tube is inserted through the median
cricothyroid ligament — the quickest and easiest access
to the airway.
 To avoid permanent laryngeal stenosis —
cricothyroidotomy must be converted to a standard
tracheotomy within days.

ARYTENOID CARTILAGES
 Almost pyramidal in
shape,
 with
 3 surfaces,
 a base, and
 an apex.
 Each triangle-shaped base
articulates with the
cricoid cartilage by way
of a diarthrodial joint.
 Base has 2 processes:
 Anteromedially directed
vocal process – vocal
ligament is attached
 Short, broad, laterally
projecting Muscular
process – lateral and
posterior cricoarytenoid
muscles are attached

 Arytenoid has 3
surfaces
1. Posterior surface —
Transverse and oblique
arytenoid muscles attach
2. Medial surface – covered
with mucous-secreting
laryngeal mucosa.
3. Anterolateral surface –
insertion of
 thyroarytenoid muscle,
 part of the vocalis
muscle,and
 the vestibular ligament.
 The apex of the arytenoid
cartilage supports the
corniculate cartilage

 Cricoarytenoid fixation may occur from arthritis or
perichondritis (intubation
injury) and limit vocal fold mobility.
 Cricoarytenoid subluxation during blind intubation
with a lighted stylet.
 Arytenoidectomy through an external or endoscopic
approach may alleviate
arytenoid fixation or paralysis.
 submucosal arytenoidectomy which preserves an
intact laryngeal mucosa

CORNICULATE CARTILAGES ( OF SANTORINI )
 small fibroelastic nodules
that sit on the apices of the
arytenoid cartilages.
 It has little functional
importance in humans
 CUNEIFORM CARTILAGES (OF
WRISBERG)
 rod-shaped (like ancient
cuneiform script).
 situated in the
aryepiglottic folds anterior
to the corniculate cartilages,
 may be entirely absent.

TRITIATE
CARTILAGE
an occasional,
minute nodule.
 located in the
posterior margin of
the thyrohyoid
membrane

EPIGLOTTIS
 Oblong leaf shaped
 Located behind the root of the
tongue and the body of the hyoid
bone and in front of the laryngeal
entrance (laryngeal aditus or
vestibule).
 It has:
 2 ends— upper & Lower
 2 surfaces— Anterior &
Posterior
 2 Lateral borders
 Upper end:broad
 lower end: narrow –―petiolus /
stalk ‖attaches to inner surface
of thyroid cartilage below
thyroid notch by the
thyroepiglottic ligament
 It attaches to the posterior
body of the hyoid bone via the
hyoepiglottic ligament
 it lies dorsal to the thyroid
cartilage and thyrohyoid
membrane, guarding the laryngeal
entrance.

 The space between the anterior surface of the
epiglottis and the thyrohyoid membrane and
thyroid cartilage is called the preglottic space
 The epiglottis is attached to the thyroid
cartilage by the thyroepiglottic ligament.
 The aryepiglottic folds and the quadrangular
membranes attach to the lower part of the
lateral margins of the epiglottis.

 Acute epiglottiditis, may cause airway
obstruction in children.
 To rule out foreign bodies, a lateral x-ray may
be ordered if the general condition of the child
permits.
 Laryngeal visualization must be done in the
operating room to avoid airway
occlusion, aspiration, and cardiac arrest.
 Intubation and tracheostomy are the procedures
of choice

LARYNGEAL LIGAMENTS AND MEMBRANES
Membranes — Extrinsic – Thyrohyoid membrane
Crico tracheal membrane
Intrinsic — Quadrangular
membrane
Conus elasticus
 Ligaments & Folds
 Epiglottic ligaments
 Aryepiglottic fold
 Vestibular ligament (vestibular folds or false
vocal cords)
 Vocal ligaments

LARYNGEAL MEMBRANES
THYROHYOID
MEMBRANE
 provides an extensive
connection between the
thyroid cartilage and the
hyoid bone bilaterally and
anteriorly.
 Extending from the upper
border and the greater
horns of the hyoid bone to
the superior horns of the
thyroid cartilage and its
laminae
 Thickens anteriorly,
forming the median
thyrohyoid ligament
 Thickened posterior
margin on each side is
called the lateral
thyrohyoid ligament.

 The superior laryngeal
neurovascular bundle
may be injured by
surgical approaches to
the pharynx.
 One must observe
great care when
dissecting the greater
cornu of the hyoid
bone and the superior
horn of the thyroid
cartilage during various
pharyngotomy
approaches

THE CRICOTRACHEAL MEMBRANE
 connects the most
superior tracheal
cartilage with the
inferior border of the
cricoid cartilage

INTRINSIC MEMBRANES
 connect the laryngeal
cartilages with each
other to regulate
movement.
 There are 2
intrinsic membranes :
1. Conus Elasticus
and
2. Quadrangular
membranes.

CONUS ELASTICUS
 Conus Elasticus connects the
cricoid cartilage with the thyroid
and arytenoid cartilages.
 composed of dense
fibroconnective tissue with
abundant elastic fibers.
 Having 2 parts
1 .Medial cricothyroid ligament —
connects the anterior part of the
arch of the cricoid cartilage with the
inferior border of the thyroid
membrane.
2. Lateral cricothyroid membranes
originate on the superior surface of
the cricoid arch and rise superiorly
and medially to insert on the vocal
process of the arytenoid cartilages
posteriorly, and to the interior
median part of the thyroid cartilage
anteriorly.
 Its free borders form the VOCAL
LIGAMENTS

QUADRANGULAR MEMBRANE
 Extends from the sides
of the epiglottic cartilage
anteriorly to the
anterolateral surface of
the arytenoid cartilage
and posteroinferiorly to
the corniculate cartilage.
 With its covering of
mucous membrane forms
the aryepiglottic fold
superiorly and vestibular
ligament inferiorly.
 it forms the medial wall
of the piriform recess

 The paired Quadrangular
Membranes connect the
epiglottis with the arytenoid
and thyroid cartilages.
 Course posteriorly downward
and attach to the corniculate
cartilages and the lateral
surfaces of the arytenoids.
 The cuneiform cartilages are
embedded within the
aryepiglottic folds.
 The free inferior borders of
the quadrangular membranes
form the ventricular ligaments,
also known as the false vocal
folds.

LIGAMENTS & FOLDS OF LARYNX
 Epiglottic ligaments
 Aryepiglottic fold
 Vestibular ligament (vestibular folds or false
vocal cords)
 Vocal ligaments

1 . EPIGLOTTIC LIGAMENTS AND
FOLDS
 Hyoepiglottic ligament
 Thyroepiglottic ligament
 Median glossoepiglottic
ligament
 Lateral glossoepiglottic
or
pharyngoepiglottic fold,
 attached between the base
of the epiglottic cartilage
and the pharyngeal wall at
the root of the tongue

2 . ARYEPIGLOTTIC FOLDS
 one on each side,
 contain the aryepiglottic
muscles.
 associated with the
superior border of the
quadrangular membrane.
 Both aryepiglottic folds
constrict the entrance to
the larynx and protect
the respiratory pathway
by not permitting food,
liquids, and foreign bodies
to enter the larynx and
trachea.

3 . VESTIBULAR FOLDS
(FALSE VOCAL CORDS)
 formed by the inferior edge of
the quadrangular membrane.
 Attached in front to the
thyroid cartilage just below the
attachment of the epiglottic
cartilage
 Connected behind to the
anterolateral surfaces of the
arytenoid cartilages.
 The vestibular ligaments are
located just above the vocal
ligaments, separated from them
by bilateral ellipsoid spaces
called the laryngeal ventricles.
 Overlap the true vocal folds
just prior to a cough or sneeze
— reinforcing the resistance
offered by the true vocal folds
against the internal expiratory
pressures.

4.VOCAL LIGAMENTS, VOCAL CORDS,
AND VOCAL FOLDS
 The thickened,
ligamentous, upper
edges of the elastic
tissue of the conus are
the vocal ligaments or
vocal cords.
 Extend from the medial
extremities of the
laminae of the thyroid
cartilage in the midline
anteriorly (forming the
anterior commissure) to
the apices of the vocal
processes of the
arytenoid cartilages on
each side posteriorly.

STRUCTURE OF VOCALCORD
 Histologically 5 layers:
 LAYER 1: is the squamous epithelial lining. It is very thin and helps to hold
the shape of the vocal fold. This layer doesnot contain any mucous glands.
 LAYER 2: superfical layer of the lamina propria. It is composed of loose
fibers and matrix .
 This layer contains only minimal elastic and collagenous fibers and offers
least resistance to vibration. The integrity of this layer is vital for proper
phonatory function.
 LAYER 3: intermediate layer of lamina propria.
 It contains a higher concentration of elastic and collagenous fibers when
compared to layer 2. This layer is thickened at the anterior and posterior
ends of the vocal folds. These thickened regions are known as anterior and
posterior macula flava. These structures provide protection to the vocal
folds from mechanical damage.
 LAYER 4 : deep layer of lamina propria.
 It contains a dense collection of elastic and collagenous fibers. This layer
along with the intermediate layer constitute the vocal ligament. Some of
the collagenous fibers present here gets inserted into the vocalis muscle.
LAYER 5: formed by the vocalis muscle. The fibers of this muscle run
parallel to the direction of the vocal fold.

 Vocalis muscle is infact a portion of
thyro arytenoid muscle.
 At the anterior most portion of the vocal
fold a mass of collagenous tissue is
present--known as the anterior
commissure tendon
or Broyle's ligament.
 This ligament gets attached to the inner
area of thyroid cartilage which is
devoid of perichondrium.
 Lacking a submucosa and blood vessels,
the vocal ligaments appear to be pearly
white and shiny.
 The space between the true vocal cords
(the intermembranous space) is known as
the rima glottidis

RIMA GLOTTIDIS
Subdivided into 2 parts,
 2/5 – intercartilaginous
part (respiratory
glottis,or interarytenoid
space), between the
arytenoid cartilages and
 3/5 — the
intermembranous part
or glottis vocalis.

 The epithelium of the true vocal cords does not have
lymphatics. Therefore, metastatic disease is a rare
phenomenon.
 The vocal folds are devoid of lymphatics, and it infact
clearly forms the watershed zone between the upper and
the lower group of lymphatics.
 The pathway of metastasis of glottic cancer is via the
Delphian node or paratracheal nodes and finally nodes of
the superior mediastinum.

LARYNGEAL MUCOSA
 Is mostly of the respiratory type called ciliated columnar
epithelium,
 certain areas of the larynx covered with
stratified squamous epithelium are-
 upper area of the anterior , dorsal epiglottic surfaces,
 the ventral half of the aryepiglottic folds, and
 the vocal cords.
 Mucous membrane of the supraglottic larynx is a
downward continuation of the oropharyngeal mucosa.
 Infraglottic region of the larynx is made of normal
respiratory mucosa
 Mucous glands are found at the posterior surface of the
epiglottis, aryepiglottic fold, and laryngeal appendices.

LARYNGEAL SPACES
 Internal laryngeal
spaces :
 vestibule,
 ventricles,
o subglottic or
infraglottic spaces
o External laryngeal
spaces
 Paraglottic space
 pre-epiglottic. Space

INTERNAL SPACES (LARYNGEAL CAVITY)
VESTIBULE
 pyramid -shaped space
extends from the
laryngeal inlet or aditus
to the vestibular folds
(false vocal cords).
 Bounded ventrally by
the posteroinferior
surface of the
epiglottis, dorsally by
the corniculate
cartilages and apices of
the arytenoids, and
laterally by the
aryepiglottic folds and
the piriform recesses.

LARYNGEAL VENTRICLES
 sinuses (of Morgagni), are
diverticula of the interval
between the false and true
vocal cords.
 It is lined internally by
mucosa and covered
externally by a very thin
layer of elastic tissue and
the thin thyroarytenoid
muscle.
 The anterior end of the
ventricle may possess an
additional external
expansion, the laryngeal
saccule,
 This extends upward deep
to the internal face of the
thyroid cartilage.

SURGICAL CONSIDERATIONS.
 Enlargement of the laryngeal
saccule is often referred to
as a laryngocele.
 Any obstruction of the
laryngeal ventricle, such as a
ventricular carcinoma, may
lead to the formation of a
laryngocele.
 A laryngocele may bulge
through the aryepiglottic fold
and obstruct the endolarynx
( internal laryngocele ).
 It may be present outside of
the thyrohyoid membrane (
external laryngocele ).
 The enlargement may even be
a combined
internal and external
laryngocele

SUBGLOTTIC (INFRAGLOTTIC) SPACE
 the distal part of the
laryngeal cavity.
 extends from the glottis
to the inferior border of
the cricoid cartilage.
 The subglottic space
begins below the curve
formed by the vocal fold
to the lower end of
cricoid cartilage
 SURGICAL
IMPORTANCE :
 Narrowest area in
infants , so edema
obstruction &
respiratory distress
occur early

EXTERNAL SPACES
 Supraglottic laryngeal area is subdivided into 3
laryngeal spaces
 Paired Lateral Paraglottic Spaces
 One midline Pre-Epiglottic Space

( TUCKER’SPARAGLOTTIC SPACES
SPACE)
 Bounded laterally by
the thyroid cartilage,
 inferomedially by the
conus elasticus,
 medially by the
ventricle and the
quadrangular
membrane

PRE-EPIGLOTTIC SPACE ( BOAYER’S SPACE )
 Bounded superiorly by the
hyoepiglottic ligament,
anteriorly by the thyrohyoid
membrane and ligament, and
Posteroinferiorly by the
epiglottis and
thyroepiglottic ligament.
 The pre-epiglottic space
forms an inverted pyramid.
 continuous with the superior
portion of the
paraglottic space.
 contains abundant fat, blood
vessels, lymphatics,and
mucosal glands.

 Epiglottic (supraglottic) carcinoma may spread
through perforations in the epiglottis into the
pre-epiglottic space.
 Since the pre-epiglottic space communicates
laterally with the paraglottic spaces, a
carcinoma is free to spread beyond the internal
boundaries of the larynx.
 Therefore, supraglottic laryngectomy may be
contraindicated

LARYNGEAL JOINTS
 2 pairs of synovial joints
 Between the major cartilages of the larynx:
 the cricothyroid and
 the cricoarytenoid.

1.CRICOTHYROID
JOINT
 The joints between the
inferior cornua of the
thyroid cartilage and the
sides of the cricoid
cartilage are synovial
 The primary movement at
the joint is rotation around
a transverse axis which
passes transversely through
both cricothyroid joints
 The effect of these
movements is to lengthen
the vocal folds, provided the
arytenoid cartilages are
stabilized at the
cricoarytenoid joint.
 This may also increase vocal
fold tension

2.CRICOARYTENOID JOINT
 The crico-arytenoid joints
between articular facets on
the superolateral surfaces
of the cricoid cartilage and
the bases of the arytenoid
cartilages enable the
arytenoid cartilages to
slide away or towards each
other and to rotate so that
the vocal processes pivot
either towards or away
from the midline. These
movements abduct and
adduct the vocal ligaments
3.ARYTINOCORNICULATE
JOINT
 Synovial or cartilaginous
joints link the arytenoid
and corniculate cartilages

LARYNGEAL MUSCLES
 Extrinsic muscles — which move the entire
larynx,
 Intrinsic muscles — which move the vocal cords.

 ELEVATORS OF THE PHARYNX
 The Suprahyoid Muscles
 Digastric
 Stylohyoid
 Mylohyoid
 Geniohyoid
 The Longitudinal Muscles of the
Pharynx
 Stylopharyngeus
 Salpingopharyngeus
 Palatopharyngeus
DEPRESSORS OF THE PHARYNX:
 The Infrahyoid Muscles
 Sternohyoid
 Sternothyroid
 Omohyoid
EXTRINSIC MUSCLES

INTRINSIC MUSCLES
 The intrinsic muscles
are:
 Cricothyroid
 Posterior cricoarytenoid
 Lateral cricoarytenoid
 Arytenoid with its
transverse and oblique
fibers
 Thyroarytenoid and its
thyroepiglottic and
components

MUSCLES CONTROLLING THE LARYNGEAL
INLET
 Oblique arytenoid
 Aryepiglottic muscle

MOVEMENTS OF THE VOCAL CORDS
Adduction
Abduction
Folds closed (adducted) Folds open (abducted)
(View from above)
Glottis (space between folds)

ADDUCTORS OF THE VOCAL CORDS
Lateral cricoarytenoid
Transverse arytenoid

ABDUCTOR OF THE VOCAL CORDS
Posterior
cricoarytenoid

MUSCLE INCREASING THE LENGTH & TENSION OF
THE VOCAL CORDS
 Cricothyroid: increases the
distance between the angle of
the thyroid cartilage & the
vocal processes of the
arytenoid cartilages, and
results in increase in the
length & tension of the vocal
cords

MUSCLE DECREASING THE LENGTH & TENSION OF
VOCAL CORDS
 Thyroarytenoid
(vocalis): pulls the
arytenoid cartilage
forward toward the
thyroid cartilage and
thus shortens and
relaxes the vocal
cords

SPHINCTERIC FUNCTION OF THE
LARYNX
There are two sphincters:
 At the inlet: used only
during swallowing
 At the rima glottis: used in
coughing and sneezing

SHAPE OF GLOTTIS
Quiet Respiration Forced Inspiration

SHAPE OF GLOTTIS
Normal voice Whisper

BLOOD SUPPLY OF LARYNX :
 ARTERIAL SUPPLY
 Upper Larynx
 External carotid artery
 Superior thyroid artery
 Superior laryngeal artery
 Lower Larynx
 Subclavian artery
 Thyrocervical artery
 Inferior thyroid artery
 Inferior laryngeal artery

VENOUS
DRAINAGE
 Upper Larynx
 Superior laryngeal
vein
 Superior thyroid vein
 Internal jugular vein
 Lower Larynx
 Inferior laryngeal
vein
 Inferior thyroid vein
 subclavian vein

LYMPHATIC DRIANAGE
 SUPRA GLOTTIC AREA
superior lymphatics drain to
the upper deep cervical
nodes, located at the level of
the carotid bifurcation.
 Some drainage passes to
prelaryngeal nodes.
 INFRA GLOTTIC AREA
drain to the pretracheal
lymph nodes of the proximal
trachea anteriorly
paratracheal nodes laterally
and then to the deep cervical
and superior mediastinal
nodes.

GLOTIC AREA ( VOCAL FOLDS) is relatively
devoid of lymphatics.
 The space deep to the thin mucosa of the true vocal
cords, which is called Reanke's space, has no direct
lymphatic drainage.
 The spread of carcinoma is, likewise and fortunately,
retarded until an invasive process involves tissue
peripheral to the true vocal cord.
 DELPHIAN NODE :
 a midline prelaryngeal lymph node, adjacent to the
thyroid gland, enlargement of which is indicative of
metastasis from thyroid or laryngeal carcinoma.

SURGICAL IMPORTANCE
 Elective dissection of node
levels II to IV for N-0
laryngeal and hypopharyngeal
carcinoma,
 Bilateral selective dissection
is justified by the prevalence
of bilateral metastases in
midline and bilateral tumors.
 The superior neurovascular
bundle may be injured during
anterior and lateral
pharyngotomy approaches to
the larynx.
 Branches of the cricothyroid
artery may be accidentally
injured during emergency
cricothyroidotomy.

 Supplied by Vagus nerve:
 Superior laryngeal nerve
1. Internal branch (sensory) –
areas above the glottis
2. External branch (motor and
sensory)
 Motor – Cricothyroid muscle
 Sensory – Anterior
infraglottic larynx at level of
cricothyroid membrane
 Inferior (recurrent)
laryngeal n.
 Motor – all intrinsic laryngeal
muscles of SAME side
(except cricothyroid) and
interarytenoid muscle of
BOTH sides
 Sensory – areas below the
glottis
NERVE SUPPLY

ANATOMY OF LARYNX

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