Anatomy of Larynx Regards, Dr Diptiman Baliarsingh +919438436775

1. ANATOMY
OF
LARYNX
Dr. Diptiman Baliarsingh
1st Year PG, Dept. of ENT,
Hi-Tech Medical College & Hospital, Bhubaneswar

2. EMBRYOLOGY
 During 4th wk, the tracheo-bronchial diverticulum
appears in the ventral wall of primitive pharynx, just
below hypobrachial eminence.
 The edges of this groove form oesophago-tracheal
septum, which fuses caudally leaving a slit like
aperture cranially.
 The cranial end of tube forms larynx & trachea
 The caudal end of tube forms bronchi & lungs
 The tube is lined by endoderm which forms the
epithelial lining of entire respiratory system.

3.  Arytenoid swellings appear on both sides of
tracheo-bronchial diverticulum. The Aryteniod
swellings grow upwards and deepen to produce
Ary-epiglottic folds
 Hypobrachial eminence forms Epiglottis
 Glottis forms just above the primitive aperture
 Thyroid cartilage develops from the ventral ends of
the cartilages of the 4th pharyngeal arch
 Cricoid cartilage and cartilages of trachea develop
from 6th arch
 Superior & recurrent laryngeal branches of vagus
nerve are derived from 4th & 6th arches which
supply the larynx.

4. EMBRYOLOGICAL DEVELOPMENT OF LARYNX
Structure Source
Laryngeal mucosa Endoderm of cephalic part of
foregut
Laryngeal cartilages Mesenchyme
Epiglottis Hypobranchial eminence
Upper part of thyroid cartilage 4th branchial arch
lower part of thyroid cartilage,
cricoid, corniculate, and cunei-form
cartilages
6th branchial arch
Intrinsic muscles of larynx 6th branchial arch

6. GENERAL ANATOMY
 Extent
 From laryngeal inlet to inferior border of cricoid cartilage
 3rd to 6th cervical vertebrae
 Little higher in women
 VC lie at C5 level in adults, C3/C4 in infants
 Infantile larynx is smaller & funnel shaped
 It is narrowest at the junction of sub-glottic larynx
with trachea.
* Slight swelling may result in marked airway obstruction
 Laryngeal cartilages are much softer in infants and
collapse more easily on forced inspiration

7.  As the larynx grows there is little difference in size
between boys and girls till puberty, after which A-P
diameter almost doubles in men, with a final A-P
dia. of
 36mm in Men
 26mm in Women
 Larynx is divided into 3 parts by False & True vocal
cords
 Supraglottis
 Glottis
 Subglottis

8.  Supraglottis consists of
 Superiorly - epiglottis & aryepiglottic folds
 Lower border - the ventricular bands (false cords)
 Glottis consists of
 Vocal cords
 Anterior commissure
 Posterior commissure
 Subglottis consists of
 Upto lower border of cricoid
 It becomes trachea at lower border of cricoid

9. INFANT LARYNX
 Position: Infant larynx is situated higher in the neck.
Vocalcords lie at C3/C4 level and during swallowing
go up to C1/ C2 level. In adults vocal cords lie at C5
level.
 Cartilages: Laryngeal cartilages in infants are soft
and collapse easily.
 Epiglottis: It is omega shaped.
 Arytenoids: They are relatively large and cover
significant posterior part of glottis.
 Thyroid: It is flat.
 Cricoid: The diameter of cricoid is smaller than glottis.

10.  Cricothyroid and thyrohyoid spaces: They are very
narrow. Hyoid bone overlaps thyroid and thyroid
overlaps cricoid.
 Size: The larynx of an infant is smaller and has a
narrower lumen
 Shape: It is conical and funnel-shaped
 Submucosal tissue: It is thick and loose and
becomes easily edematous in response to trauma
or inflammation

11. LARYNGEAL FRAMEWORK - ANTERIOR VIEW

12. LATERAL VIEW OF LARYNX SHOWING
CARTILAGES AND LIGAMENTS

13. POSTERIOR VIEW OF LARYNX SHOWING
CARTILAGES AND LIGAMENTS

14. FRAMEWORK OF LARYNX
 Consists of
 Bone – Hyoid bone
 Cartilages – 3 paired & 3 unpaired
 3 unpaired – Thyroid cartilage
Cricoid cartilage
Epiglottis
 3 paired – Arytenoid cartilage
Corniculate cartilage
Cuneiform cartilage
 Ligaments – Extrinsc & Intrinsic
 Membranes
 Muscles – Extrinsic & Intrinsic

16. HYOID BONE
 U-shaped bone
 Provides upper attachment for extrinsic muscles of
larynx
 Suspends the larynx in theneck
 3 parts
 Body – present anteriorly
 Greater cornua – projects backwards
 Lesser cornua – 2 small conical eminences

18. LARYNGEAL FRAMEWORK - ANTERIOR VIEW

19. THYROID CARTILAGE
 2 lamina fused anteriorly in midline giving rise to
laryngeal prominence
 Angle of fusion –
 90 degree in Men
 120 degree in women
 The posterior border of each lamina is prolonged
above & below to form superior & inferior cornua
 Superior cornua - long & narrow
- curves upwards, backwrds & medially
*Lateral thyroid ligament is attached
 Inferior cornua - shorter and thicker
- curves downward & medially
*small oval facet jt. on which articulates cricoid cart.

20.  External Surface of Thy. cart.
 On each lamina is a oblique line, curves downwards &
forwards from superior thyroid tubercle to inferior thyroid
tubercle.
 The line marks the attachment of
 Thyrohyoid
 Sternothyroid
 Inferior constrictor muscles
 Inner aspect of Thy. Cart.
 Thyroepiglottic ligament is attached just below the
thyroid notch in midline
 Below this on each side of midline is attached
 Vestibular & Vocal ligaments
 Thyroaryteniod Muscle
 Thyroepiglottic Muscle
 Vocalis Muscle

23.  The fusion of the anterior ends of the two vocal
ligaments produce Anterior commissure
 The superior border of each lamina gives
attachment to thyrohyoid ligament
 The inferior border gives attachment to cricothyroid
ligament

24. POSTERIOR VIEW OF LARYNX SHOWING
CARTILAGES AND LIGAMENTS

25. LARYNGEAL FRAMEWORK

26. CRICOID CARTILAGE
 It is the only complete cartilagenous ring in the
airway
 It forms the inferior part of the larynx
 It has a deep broad lamina posteriorly & narrow
arch anteriorly with a facet for articulation with the
inferior cornu of the thyroid cartilage
 The lamina has sloping shoulders on which the
articular facets for the arytenoids are found
 A vertical ridge in midline of lamina give attachment
to longitudinal muscle of oesophaus
 Shallow concavity on each side gives origin to
posterior cricoaryteniod

27. CRICOID CARTILAGE

29. EPIGLOTTIS
 Thin leaf like sheet of elastic fibrocartilage
 Projects upwards behind the tongue and hyoid
bone
 It is attached
 Inferiorly – to thyroid cartilage, just below thyroid notch
in midline by thyroepiglottic ligamnet
 Anteriorly – to hyoid bone by hyoepiglottic ligament
 Space between these two ligaments forms pre-epiglottic
space
 From the sides of epiglottis, aryepiglottic folds pass
down to the apex of aryteniods

30. SAGITTAL SECTION OF LARYNX

31.  The posterior surface of Epi. is indented by
numerous small pits into which mucus glands
project
 The anterior surface is coverd by mucous
membrane superiorly & forms the posterior wall of
vallecula
 The mucous membrane overlying epiglottis is
reflected on base of tongue forming
 Glossoepiglottic fold – midline
 Lateral glossoepiglottic fold – laterally

32. EPIGLOTTIS

33. ARYTENOID CARTILAGES
 Irregular, three sided pyramid
 with a
 Forward projection – Vocal Process – attached Vocal
folds
 Lateral projection – Muscular process – attached
posterior cricoarytenoid & lateral cricothyroid muscles
 Anterolateral surface – is divided into two fossa by a
crest from apex into
 Upper triangular fossa – attachment to Vestibular
ligament
 Lower triangular fossa – attch. to Vocalis & Lateral
cricoaryteniod muscle

34. ARYTENOIDS

35.  The apex is curved backwards & medially, and is
flattened for articulation with corniculate cartilage.
 The medial surface is covered with mucous
membrane
 Posterior surface is covered by transverse
aryteniod muscle
 The base is concave and provides smooth surface
for articulation with cricoid
*this is a synovial joint with lax capsular
ligaments allowing -
1. rotarory movements
2. medial & lateral gliding movements
 Post. cricoarytenoid ligament prevents forward
movement of arytenoid cartilage

36. ATTACHMENTS OF ARYTENOIDS

37. CORNICULATE & CUNEIFORM CARTILAGES
 Corniculate Cartilages (of Santorini)
 2 small conical nodules of elastic fibrocatilage
 Articulate by a synovial joint with the apices of aryteniod
cartilages
 Situated in the posterior part of aryepiglottic fold
 Cuneiform Cartilages (of Wrisberg)
 2 small elongated flakes of fibroelastic cartilage (rod
shaped cart.)
 One in each margin of aryepiglottic folds

38. JOINTS
 Cricoarytenoid joint:
 This synovial joint is formed between the base of
arytenoid and a facet on the upper border of cricoid
lamina.
 Two types of movements are possible at this joint;
rotatory and gliding.
 The rotatory movement occurs at a vertical axis and
abducts or adducts the vocal cord.
 Arytenoids glide laterally and medially and help in
closing or opening the posterior part of glottis.
 Cricothyroid joint:
 This synovial joint is formed between the inferior cornua
of thyroid cartilage and a facet on the cricoid cartilage.

39. LIGAMNETS & MEMBRANES
 EXTRINSIC LIGAMENTS
 They connect laryngeal cartilages to hyoid bone above
& trachea below
 Superiorly – Thyrohyoid membrane stretches between
upper border of thyroid cartilage & posterior surface of
the body & greater cornua of hyoid
 The membrane is a fibroelastic tissue & is re-enforced
by fibrous tissue in
 midline as median thyrohyoid ligament &
 posteriorly as lateral thyrohyoid ligament ( ligament often
contains a small nodule of cartilage – Cartilago Triticea)
 The membrane is pierced by Internal branch of Sup.
Laryngeal Nerve & Sup. Laryngeal Vessels
 Cricotracheal ligament unites lower border of cricoid
with first tracheal ring

40.  INTRINSIC LIGAMENTS
 They
 Connect the laryngeal cartilages together
 Strengthen the capsule of intercartilagenous joints
 Form a broad sheet of fibroelastic tissue – fibroelastic
membrane
 Fibroelastic Membrane is divided into upper & lower part
by laryngeal ventricle
 Upper Quadilateral Membrane – extends between
lateral border of epiglottis & arytenoid cartilages
 Upper margin forms aryepiglottic fold
 Lower margin forms vestibular ligament underlying the
vestibular fold (false cords)

41. SAGITTAL SECTION OF LARYNX

43.  Lower part is thicker containing elastic fibres, called as
cricovocal lig. / cricothyroid lig. / conus elasticus
 It is attached
 Above to thyroid cart. anteriorly & vocal process of arytenoid
posteriorly
 Below to upper border of cricod cartilage
 The free upper border of this memb. forms the Vocal
Ligament (true cord)
 Anteriorly there is thickening of this membrane -
forming cricothyroid ligament, which connects cricoid
and thyroid cartilages in the midline.

45. LATERAL VIEW OF LARYNX SHOWING
CARTILAGES AND LIGAMENTS

46. LATERAL VIEW OF LARYNX AFTER REMOVING RIGHT
LAMINA OF THYROID CARTILAGES

47. CORONAL SECTION OF LARYNX

48. MUSCLES OF LARYNX
 Extrinsic Muscles – attach larynx to surr. structures
& maintain positing of larynx in neck
 Infrahyoid group - Thyrohyoid,
- Sternothyroid,
- Sternohyoid.
 Suprahyoid group - Mylohyoid,
- Geniohyoid,
- Stylohyoid,
- Digastric,
- Stylopgaryngeus,
- Palatopharyngeus,
- Salpingopharyngeus.

49. EXTRINSIC MUSCLES OF LARYNX

50.  Intrinsic Muscles – are all paired (excp. Tr. A) & move
the cartilages in the larynx & regulate the mechanical
properties of larynx
 Open & Close glottis - Posterior Cricoarytenoid
- Lateral Cricoarytenoid
- Transverse Arytenoids(unpaired)*
- Oblique Arytenoids(paired)
 Control tension of VC - Thyroarytenoids (vocalis)
- Cricothyroid
 Alter the shape of laryngeal inlet
- Aryepiglotticus
- Thyroepiglotticus

51. VOCAL CORDS
 Abductors:
 Posterior cricoarytenoid
 Adductors:
 Lateral cricoarytenoid
 Interarytenoid (transverse and oblique arytenoids)
 Thyroarytenoid (external part)
 Tensors:
 Cricothyroid
 Relaxers:
 Vocalis
 Thyroarytenoid (internal part)

52. INTRINSIC MUSCLES OF LARYNX AND THEIR
ACTIONS

53. INTRINSIC MUSCLES OF LARYNX AS SEEN ON
ITS POSTERIOR VIEW

54. INTRINSIC MUSCLES OF LARYNX AS SEEN ON
ITS LATERAL VIEW

55. LATERAL VIEW OF LARYNX SHOWING CRICOTHYROID
MUSCLE, CARTILAGES AND LIGAMENTS

56. EXTRINSIC MUSCLES OF LARYNX
 INFRAHYOID GROUP
1. Thyrohyoid
 Origin - Oblique line of thyroid lamina
 Insertion - Inferior border of the greater cornu of
the Hyoid
 Function - Elevates the larynx on a fixed hyoid or
depresses the hyoid on a fixed larynx
 Innervation - Hypoglossal (C1 root)

58. 2. Sternothyroid
 Origin - Posterior surface of manubrium and edge
of the first costal cartilage
 Insertion - Oblique line of the thyroid lamina
 Function - Depresses the larynx
 Innervation - Ansa cervicalis (C2, 3 roots)
3. Sternohyoid
 Origin - Clavicle and posterior surface of the manubrium
 Insertion - Lower edge of the body of the hyoid
 Function - Depresses the larynx by lowering the hyoid
 Innervation - Ansa cervicalis (C1, 2, 3 roots)

60.  SUPRAHYOID GROUP
1. Mylohyoid
 Origin – Mylohyoid line in inner aspect of mandible
 Insertion – Midline raphe & body of hyoid
 Function – raises & pulls hyoid anteriorly
 Innervation – Nr. to Mylohyoid
2. Geniohyoid
 Origin – Genial tubercle on mandible
 Insertion – upper border of the body of hyoid
 Function – raises & pulls the hyoid forwards
 Innervation – Hypoglossal (C1 root)

62. 3. Stylohyoid
 Origin – back of the styloid process
 Insertion – base of greater cornu of the hyoid
 Function – retractor & elevator of hyoid for
swallowing
 Innervation – facial nerve
4. Digastric
 Origin – Digastric notch on the medial surface of
the mastoid process
 Insertion – Lower border of the mandible (a fibrous sling
holds the tendon to the lesser cornu of hyoid)
 Function –
Anterior belly – pulls the hyoid anteriorly & up
Posterior belly – pulls the hyoid posteriorly & up
 Innervation - Ant. belly – Nr to mylohyoid
Post. belly – Facial Nr

64. 5. Stylopharyngeus
 Origin – Medial aspect of styloid process
 Insertion – Post. border of lamina of thyroid cart.
 Function – Elevates the larynx
 Innervation – Glossopharyngeal Nr
6. Palatopharyngeus
 Origin – Palatine aponeurosis & post margin of hard palate
 Insertion – Post. border of thyroid alar & cornua
 Function – helps tilts the larynx forwards
 Innervation – Accessory Nr (pharyngeal plexus)
7. Salpingopharyngeus
 Origin – Eustachian Tube
 Insertion – Post. border of thyroid cartilage
 Function – Elevates the larynx
 Innervation – Pharyngeal plexus

66. SUPERIOR VIEW OF THE INSIDE OF LARYNX AS
SEEN DURING LARYNGOSCOPIC EXAMINATION

67. INTRINSIC MUSCLES OF LARYNX
 OPEN & CLOSE THE GLOTTIS
1. Posterior Cricoarytenoid
 Origin – Lower & medial surface of back of cricoid lamina
 Insertion – it fans out to be inserted into the back of
the muscular process of the arytenoid
 Function – Opens the glottis
(Upper horizontal fibres – rotate the arytenoids & move the
muscular process towards each other separating the vocal
process & abducting the cords
Lower vertical fibres – draw the arytenoids down the sloping
shoulders of the cricoid separating the lamina)
 Effect - abducts & elevates the tip of vocal process
- vocal fold becomes elongated & thin

68. INTRINSIC MUSCLES OF LARYNX

69. INTRINSIC MUSCLES OF LARYNX AND THEIR
ACTIONS

70. 2. Lateral Cricoarytenoid
 Origin – sup. border of lat. part of the arch of cricoid
 Insertion – muscular process of arytenoid
 Function – adductus & lowers the tip of the vocal process by
rotating the arytenoids medially
 Effect – Vocal fold adducted, lowered, elongated & thinned
3. Transverse Arytenoids(unpaired)
 Origin – post. surf of muscular process & outer edge of arytenoid
 Insertion – crosses over & attaches on same point on other
arytenoid
4. Oblique Arytenoids(paired)
 Origin – post. surf of muscular process (superfi. to Tr .Ary)
 Insertion – Apex of other arytenoid
 Function – Adducts VC & controls the position of VC
 Effect – No significant effect on Vocal fold

71. INTRINSIC MUSCLES OF LARYNX

72. INTRINSIC MUSCLES OF LARYNX AND THEIR
ACTIONS

73.  CONTROL THE TENSION OF VOCAL FOLDS
1. Thyroarytenoids (Vocalis) – it is a broad sheet of
muscle lies lateral to & above the free egde of
cricovocal ligament (conus elasticus). Its lower part is
thicker and forms vocalis muscle.
 Origin – back of the thyroid prominence &
cricothyroid ligament
 Insertion – vocal process of arytenoid & anterolateral
surface of the body of arytenoid
 Effect – Lowers, shortens & thickens the vocal folds

74. STRUCTURE OF VOCAL FOLD. CROSS-SECTION

75. 2. Cricothyroid – it is the only intrinsic muscle that lies
outside the cartilagenous framework of larynx & *also
the only muscle amongst all the intrinsic muscles of
larynx which is supplied by Ext. br. of SLN, rest all being
supplied by RLN.
 Origin – lateral surface of the anterior arch of cricoid, the
fibers fan out and pass backwards in two groups
 Lower Oblique & Anterior Straight fibres
 Insertion - Lower Oblique fibres – pass backwards
and laterally to the anterior border of
the inferior cornu of thyroid cartilage.
- Anterior Straight fibres – ascend to the
posterior part of the lower border of
thyroid lamina
 Effect – Rotates the cricoid cartilage about the horizontal
axis passing through the cricothyroid joint

76. INTRINSIC MUSCLES OF LARYNX

77. INTRINSIC MUSCLES OF LARYNX AND THEIR
ACTIONS

78.  ALTER THE SHAPE OF LARYNGEAL INLET
1. Aryepiglotticus – continuation of oblique arytenoid
 Origin – posterior aspect of muscular process of
arytenoid
 Insertion – fibres pass around the apex of the opposite
arytenoid & insert into the aryepiglottic fold
 Effect – weak sphincter of laryngeal inlet
2. Thyroepiglotticus – continuation of thyroarytenoid
 Origin – back of thyroid prominence & cricothyroid
ligament
 Insertion – fibres pass upwards into aryepiglottic fold
 Effect – widens the inlet of larynx by pulling the
aryepiglottic flods slightly apart

79. THE GLOTTIS
 The glottis lies between False VC & True VC which
cover vestibular & vocal ligaments
 In glottis, laterally lies Laryngeal Ventricle (sinus of
larynx)
 In the anterior part of ventricle, the saccule of larynx
acsends between vestibular ligament & inner surf. of
thyroid cartilage.
 Laryngocele – abnormally enlarged & distended saccule
containing air
 Retension Cyst – due to obstruction of mucous glands
saccule

80.  The glottis (RIMA GLOTTIDIS) is the narrowest part of
adult laryngeal cavity & lies between VC & arytenoids on
two sides
 The size & shape of glottis varies with the activites of
VCs
 Vestibular Folds –
 2 thick folds of mucous membrane enclosing vestibular
ligament
 VL is the lower border of upper quadilateral membrane
 It is fixed – in Front – at angle of thyroid cartilage just
below attch. of epiglottic cart.
Behind – anterolateral surface of arytenoids

83.  Vocal Folds –
 Extend from the middle of the angle of thyroid cartilage
to the vocal process of arytenoid cartilage
 Underneath, there is the upper border of Conus
Elasticus
 Each fold is layered structure consisting of
1. Superficial layer of non-keratinizing stratified
squamous epithelium
2. Lamina propria – 3 distinct layers
 Superficial layer ( Reinke’s space) – contains a
fibrous substance
 Intermediate layer – contains elastic fibres
 Deep layer – contains collagen fibres
 Intermediate & Deep layer form VOCAL LIGAMENT
3. The vocalis muscle, forms the main body of VF lies
lateral & deep

84. STRUCTURE OF VOCAL FOLD - CROSS-SECTION

85.  The layered structure of vocal fold is not uniform in its
entire length.
 Anterior end of VF lies a mass of collagen fibres which are
connected to inner perichondrium of thyroid cartilage & to
deep layer of lamina propria posteriorly
 Adjacent to this mass of collagen fibres, posteriorly, lies a
mass of elastic fibres continuous with intermediate layer of
LP, called Anterior Macula Flava. A similar structure at
posterior end of membranous part of VF
 These serve as cushions to protect the ends of vocal folds
from mechanical damage caused by vocal fold vibration.
 Anterior 3/5th of VC is between vocal folds – called
Intermembranous part of cord
 Remaining 2/5th posteriorly are between vocal process of
arytenoid – called Intercartilagenous part of cord

86. MUCOUS MEMBRANES OF LARYNX
 The m.m. lining is closely attached over the posterior
surface of epiglottis, corniculate & cuniform cartilages
and all over the vocal ligament.
 Elsewhere it is loosely attached & prone to edema
 Most of larynx* is lined by pseudo-stratified cilliated
columnar ‘respiratory-type’ epithelium
 * The upper half of posterior surface of epiglottis, the
upper part of aryepiglottic fold, posterior glottis &
vocal folds are covered with non-keratinizing stratified
squamous epithelium.

87.  Mucous glands are freely distributed throughout
the mucous membrane & at particularly numerous
on the posterior half of epiglottis where they form
indentation into the cartilage & in the margins of the
lower part of the aryepiglottic folds and saccules.
 The vocal folds do not posses any glands & the
mucous membrane is lubricated by mucus from the
glands of the saccules.
* if these glands cease to function, i.e. after
radiation the the sq. epithelium of vocal cords tend
to dessicate.

88. LARYNGEAL SPACES
 PRE-EPIGLOTTIC SPACE
 Wedge shaped space
 Boundaries
 Anteriorly – thyrohyoid ligament
& hyoid bone
 Posteriorly – epiglottis (infrahyoid part)
 Superiorly – hyoepiglottic ligament
 Inferiorly – thyrpoepiglotic ligament
* Tumour may spread through
1. perforations in epiglottis
2. directly through hyo-epiglottic ligament
 Pre-epiglottic space is continous laterally with the para-epiglottic
space

89.  PARA-GLOTTIC SPACE
 Boundaries –
 Antero-Laterally – thyroid cartilage & cricothyroid membrane
 Medially – conus elasticus & quadrangular membrane
 Posteriorly – pyriform fossa
 It encompasses laryngeal ventricles & saccules
 REINKE’S SPACE
 Lies under epithelium
of VC’s
 Boundaries
 Abv & Blw – Arcuate lines
 Ant – Ant. Commissures
 Post – Vocal process of
arytenoids

90. NERVE SUPPLY OF LARYNX
 The motor and sensory supply of larynx is from
VAGUS – by superior & recurrent laryngeal nr.s
 SUPERIOR LARYNGEAL NERVE
 Arises from inferior ganglion of vagus & also receives a
branch from superior cervical sympathetic ganglion.
 It decends lateral to pharynx behind ICA & at the level of
greater horn of hyoid it divides into small external
branch & larger internal branch
 EXTERNAL BRANCH – motor supply to cricothyroid
muscle

91.  INTERNAL BRANCH – pierces thyrohyoid memb. & divides
into two main sensory & secretomotor br., & also carries
afferent fibres from neuromuscular spindles & other stretch
receptors of larynx
Upper branch – supplies mucous memb. of lower part of
pharynx, epiglottis, vallecula & vestibule of larynx
Lower branch – supplies aryepiglottic fold & mucous
membrane of larynx till level of vocal cords
 In its course beneath m.m. of medial wall of
pyriform fossa, it is accessible for inj. of LA for
providing anaesthesia for most of pyriform fossa.
 SLN ends by piercing inf. constricter muscle of
pharynx & unites with the ascending br of recurrent
laryngeal nerve. – called as Galen’s anastomosis

92.  RECURRENT LARYNGEAL NERVE
 RIGHT RLN – leaves vagus as it crosses Right sub-clavian
artery & loops under the artery ascending in the
TE groove to reach larynx
 LEFT RLN – the nerve originates from vagus as it
crosses aortic arch, it passes under the arch &
ligamentum arteriosum to reach TE groove
 In the NECK – both follow same course and pass
upwards accompanied by laryngeal branch of inferior
thyroid artery
 They pass deep to the lower border of inf. constricter
muscle & enter the larynx behind cricothyroid joint.
 Then divides into motor & sensory branches
 MOTOR BR – all intrinsic muscles of larynx, except
cricothyroid
 SENSORY BR – supplies laryngeal mucosa below the
level of vocal cords + aff. fibers from stretch receptors of
larynx

93. NERVES SUPPLYING
THE LARYNX AND
THEIR RELATIONS
ESPECIALLY WITH
ARTERIES

94.  The relationship between RLN & inferior thyroid art.
is variable
 It may cross in front of, or behind the artery or may
pass between the terminal branches of artery
 On the Rt side there is equal chance of the nerve
lying in any of three locations but on the Lt side it
usually lies posteriorly to artery.

95. LARYNGEAL VASCULATURE
 ARTERIAL SUPPLY
 Laryngeeal branches of superior & inferior thyroid arteries
 Cricothyroid br of superior thyroid artery
 The superior laryngeal artery arises from superior thyroid
artery – passes deep to thyrohyiod muscle. Together with
the int. br of SLN it pierces thyrohyiod memb. to supply
larynx
 The inferior laryngeal artery arises from inferior thyroid
artery at lower border of thyroid gl. And ascends on the
traches with RLN. It enters the larynx beneath the lower
border of inf constricter to supply it.
 The cricothyroid artery passes upper part of cricothyroid
ligament to supply larynx.

96.  VENOUS DRAINAGE
 Accompany arteries
 Superior laryngeal vein  superior thyroid vein / facial
vein  IJV
 Inferior laryngeal veins  inferior thyroid veins 
bracheocephalic vein
* some veins  middle thyroid vein  IJV
 LYMPHATICS
 Divided into two groups by vocal folds into upper &
lower drainage
 LARYNX ABOVE VOCAL FOLDS – drain by vessels
accompanying SL vein  Upper deep cervical LNs
 LARYNX BELOW VOCAL FOLDS  prelaryngeal &
pretracheal nodes  Lower deep cervical nodes
 The vocal folds have no lymphatics as they are firmly
bound down to underlying vocal ligament

97. NERVES SUPPLYING
THE LARYNX AND
THEIR RELATIONS
ESPECIALLY WITH
ARTERIES

98. FUNCTIONS OF LARYNX
 4 main funtions of larynx -
1. Protection of lower airways
 Sphincteric closure of laryngeal inlet
 Cessation of respiration
 Cough reflex
2. Phonation & speech
3. Respiration
4. Fixation of chest

99. LASTLY...
Its that part of our body which helps us to
communicate verbally with the whole world...!
From the first cry of the baby to the sweet tunes of a
melodius song...!!
Its all about LARYNX...!!!

100. THANK YOU...
 REFERENCES
 GRAY’s Anatomy - 39th Ed.
 Scott Brown’s Otorhinolaryngology & Head and Neck Surgery – 7th Ed.
 Cumming’s Otolaryngology & Head and Neck Surgery - 5th Ed.
 Mohan Bansal – 2nd Ed.
 BD Chaurasia’s – Human Anatomy 3rd Ed.