Anatomy of Larynx

2. STRUCTURE OF THE
LARYNX
• Larynx is our VOICE BOX.
• The Larynx extends from Laryngeal inlet
above to the lower border of Cricoid cartilage
below.
• Functions of Larynx :
1. Protective function
2. Voice production

4. INFANTILE LARYNX
 Lumen narrower
 More funnel-shaped
 Narrowest part is the junction of the sub-
glottic larynx with the trachea
 Cartilages are much softer and hence
collapses more easily on forced inspiration.
 Placed more high up.

5. EMBRYOLOGY
 Primitive larynx: cranial end of laryngo-
tracheal groove
 Laryngeal mucosa: endoderm
 Laryngeal cartilages & muscles:
mesenchyme

6. EMBRYOLOGY
 Epiglottis- hypobranchial eminence
 Upper part of thyroid cartilage-4th
arch
 Lower part of thyroid cartilage, cricoid,
corniculate, cuneiform, intrinsic muscles-6th
arch
 Upper part of body& lesser cornu of hyoid-2nd
arch
 Lower part of body & greater cornu of hyoid-3rd
arch

7. STRUCTURE OF LARYNX
 Laryngeal framework is formed by –
1. Cartilages
2. Membranes & ligaments
3. Muscles of larynx

8. LARYNGEAL CARTILAGES
 Paired
 Arytenoid cartilage
 Corniculate cartilage
 Cuneiform cartilage
 Unpaired:
 Thyroid cartilage
 Cricoid cartilage
 Epiglottis

9. THYROID CARTILAGE
 Hyaline cartilage
 Largest.
 Encloses the larynx
anteriorly and
laterally
 Two alae
 Ossification.

11. THYROID CARTILAGE
Internal surface
gives attachments
to –Thyro-epiglottic
ligament, paired
vocal and vestibular
ligaments and
Vocalis,Thyro-
arytenoid and
Thyro-epiglotticus
muscles.

12. CRICOID CARTILAGE
Hyaline cartilage
Strongest
Shape: Signet ring
Lamina – flat portion
Only complete
annular support of
the larynx
Articulates with
Inferior cornu of the
thyroid cartilage

13. EPIGLOTTIS
 Fibro elastic cartilage
 Leaf-shaped structure
 Petiole – small narrow
stalk like portion of
the epiglottis
attached to the
thyroid cartilage.
 Contains a tubercle on
its posterior surface.

14. EPIGLOTTIS (contd.)

15. ARYTENOID CARTILAGES
 Mostly hyaline cartilage
 Smaller in size
 Responsible for opening and closing of the
larynx
 Shape: pyramidal

16. ARYTENOID CARTILAGES
 Anterior
 Vocal process -
receives the
attachment of
the mobile end of
eachVC
 Lateral
 Muscular process
 Articulation
 Cricoarytenoid
joint

17. CORNICULATE
CARTILAGES Fibro elastic
 Cartilages of Santorini
 Small cartilages above the arytenoid and in
the aryepiglottic folds

18. CUNEIFORM CARTILAGES
 Fibro elastic cartilages
 Cartilages of Wrisberg
 Elongated pieces of
small yellow elastic
cartilage in the
aryepiglottic folds

19. TRITICEOUS CARTILAGES
 Cartilago triticea
 Small elastic
cartilage in the
lateral thyrohyoid
ligament

20. LARYNGEAL LIGAMENTS
 Extrinsic
 Thyrohyoid membrane and ligaments
 Cricothyroid membrane and ligaments
 Cricotracheal ligament
 Hyo-epiglottic ligament

21. LARYNGEAL LIGAMENTS
 Intrinsic
 Quadrangular membrane
 Conus elasticus (cricovocal membrane)
 Median cricothyroid ligament
 Vocal Ligament
 Thyroepiglottic ligament

22. EXTRINSIC LIGAMENTS
Thyrohyoid membrane
MedianThyrohyoid
ligament
– thickened median
portion
Lateral thyrohyoid
ligament
– thickened posterior
border
- where cartilago
triticea is often found

23. EXTRINSIC LIGAMENTS
Thyrohyoid membrane
pierced on each side
by:
1. Superior laryngeal
vessels
2. Internal branch of
superior laryngeal
nerve

24. EXTRINSIC LIGAMENTS
 Cricothyroid
membrane and
ligaments
 May be pierced for
emergency
tracheotomy
(cricothyrotomy)

25. EXTRINSIC LIGAMENTS
 Crico tracheal Ligament
 Attaches the cricoid
cartilage to the first
attached ring
 Hyo-epiglottic Ligament
 Connects the anterior
surface of epiglottis
with Hyoid bone.

26. HYO-EPIGLOTTIC
LIGAMENT

27. INTRINSIC LIGAMENTS
 Elastic membrane
 Divided into upper
and lower parts by the
ventricle of the larynx
 Forms the fibrous
framework of larynx.

28. INTRINSIC LIGAMENTS
 Quadrangular membrane
 Upper part of the elastic
membrane
 Boundaries
 Epiglottis , arytenoid,
corniculate cartilage,
false cord
 Forms part of wall
between upper pyriform
sinus and laryngeal
vestibule

29. INTRINSIC LIGAMENTS
 Conus elasticus (cricovocal membrane)
 Lower part of elastic membrane
 Composed mainly of yellow elastic tissue
 Median cricothyroid ligament – thickened
anteior part
 Vocal Ligament – free upper edge

30. INTRINSIC LIGAMENTS
 Boundaries
Inferior: superior border of cricoid
cartilage
Superoanterior: deep surface of angle
thyroid cartilage
Superoposterior: vocal process of
arytenoid cartilage
 Thyro-epiglottic ligament

31. INTRINSIC LIGAMENTS OF
LARYNX

32. CAVITY OF THE LARYNX
 Divided into 3 parts:
 Vestibule
 Ventricle
 Sub glottic space

33. CAVITY OF THE LARYNX
 Vestibule – boundaries:
 Anterior: posterior
surface of epiglottis
 Posterior: interval
between arytenoid
cartilages
 Lateral: inner surface
of ary-epiglottic folds
and upper surfaces of
the false cord

34. CAVITY OF THE LARYNX
• Ventricle
• Saccule – conical pouch at anterior part of the
ventricle. Lies between Inner surface of thyroid
cartilage and false cord. It has numerous mucous
glands opening into the surface of its lining
mucosa for lubricating the vocal cords.
• SUBGLOTTIC SPACE

36. RIMA GLOTTIDIS
 Space between free
margin of true cords
 Two portions –
Anterior or Inter-
membranous (3/5
th)
Posterior or Inter-
cartilagenous (2/5
th)

37. RIMA GLOTTIDIS

38. CAVITY OF THE LARYNX
False Cords (ventricular
bands)
Anteriorly: angle of
the thyroid cartilage
Posteriorly: bodies of
the arytenoid cartilage

39. CAVITY OF THE LARYNX
True cords
Voice production
Protection of lower respiratory tract
Anteriorly,: angle of thyroid cartilage
Posteriorly : vocal processes of the
arytenoid cartilages
Enclose vocal ligament and a major part of
the vocalis muscle

40. VOCAL CORDSVOCAL CORDS
 The lamina propria consists
of three layers. The most
superficial consists of fibrous
substance similar to gelatin,
and is loosely attached to
the underlying vocal
ligament
 The intermediate layer
consists of elastic fibres, and
the deep layer is formed of
collagen fibres; these two
layers collectively form the
vocal ligament
 Fibres of the vocalis muscle
form the fifth layer of the
vocal folds

41. POTENTIAL TISSUE SPACES
 REINKE`S SPACE:-
Between superficial
layer of lamina propria
and mucosa of vocal
cords.
 PARAGLOTTIC SPACE:-
between the
membranes of the
larynx and the thyroid
cartilage

42. PRE-EPIGLOTTIC SPACE
 Pre-epiglottic space of boyer:-
• Between hyoid & thyrohyoid membrane
anteriorly and infrahyoid epiglottis Posteriorly.
• Fat filled
• Sparse blood supply, so relatively radio-
resistant
• Invasion of this space- Stage T3 in TNM
classification.

43. JOINTS OF LARYNX
 Cricothyroid joint
1. Synovial joint
2. Formation -inferior
horn of thyroid
cartilage and a facet
in the cricoid
Two types movements:
Rotation
Gliding

44. JOINTS OF LARYNX
 Crico-arytenoid jt.-
1. Synovial joint
2. Formation-base of
arytenoid and facet on the
upper border of cricoid
lamina
3. Types of movement-
A) Rotatory along vertical
axis, causing abduction &
adduction of vc
b) gliding

45. MUSCLES OF LARYNX
 Extrinsic
 Intrinsic

46. EXTRINSIC MUSCLES OF
LARYNX Attach larynx to surrounding structures.
 DIRECT ELEVATORS: Stylopharyngeus,
Palatopharyngeus, Salpingopharyngeus,
Thyrohyoid
 INDIRECT ELEVATORS : Mylohyoid,
Geniohyoid , Stylohyoid & Digastric
 DEPRESSORS: Sternothyroid,
Sternohyoid,Omohyoid

47. DepressorDepressor
musclesmuscles
OriginOrigin InsertionInsertion ActionAction
SternohyoidSternohyoid manubrium ofmanubrium of
sternum andsternum and
medial end ofmedial end of
clavicleclavicle
oblique line of theoblique line of the
thyroid cartilagethyroid cartilage
depresses/stabilizesdepresses/stabilizes
the hyoid bonethe hyoid bone
OmohyoidOmohyoid superior bordersuperior border
of scapula nearof scapula near
thethe
suprascapularsuprascapular
notchnotch
inferior border ofinferior border of
hyoid bonehyoid bone
depresses, retractsdepresses, retracts
and steadies theand steadies the
hyoid duringhyoid during
swallowing andswallowing and
speakingspeaking
SternothyroidSternothyroid
MuscleMuscle
SuperiorSuperior
attachment:attachment:
oblique line ofoblique line of
thyroidthyroid
cartilage.cartilage.
InferiorInferior
attachment:attachment:
posterior surfaceposterior surface
of manubrium ofof manubrium of
sternum.sternum.
It depresses theIt depresses the
hyoid bone andhyoid bone and
larynxlarynx

48. PrimaryPrimary
ElevatorElevator
musclesmuscles
OriginOrigin InsertionInsertion ActionAction
StylopharyngeusStylopharyngeus styloidstyloid
process ofprocess of
temporaltemporal
bonebone
posterior andposterior and
superior borders ofsuperior borders of
thyroid cartilagethyroid cartilage
withwith
palatopharyngeuspalatopharyngeus
musclemuscle
elevates the pharynxelevates the pharynx
and larynx and expandsand larynx and expands
the sides of the pharynxthe sides of the pharynx
SalpingopharyngeuSalpingopharyngeu
ss
cartilaginouscartilaginous
part of thepart of the
auditoryauditory
tubetube
blends withblends with
palatopharyngeuspalatopharyngeus
musclemuscle
elevates the pharynxelevates the pharynx
and larynx and opensand larynx and opens
the orifice of thethe orifice of the
auditory tube duringauditory tube during
swallowingswallowing
PalatopharyngeusPalatopharyngeus hard palatehard palate
and palatineand palatine
aponeurosisaponeurosis
lateral wall oflateral wall of
pharynxpharynx
tenses the soft palatetenses the soft palate
and pulls the walls ofand pulls the walls of
the pharynx superiorly,the pharynx superiorly,
anteriorly and mediallyanteriorly and medially
during swallowingduring swallowing

49. SecondarySecondary
ElevatorElevator
musclesmuscles
OriginOrigin InsertionInsertion ActionAction
GeniohyoidGeniohyoid inferior mentalinferior mental
spine of mandiblespine of mandible
body of hyoidbody of hyoid
bonebone
pulls the hyoid bonepulls the hyoid bone
anterosuperiorly, and shortensanterosuperiorly, and shortens
the floor of the mouth andthe floor of the mouth and
widens the pharynxwidens the pharynx
DigastricsDigastrics anterior belly-anterior belly-
digastric fossa ofdigastric fossa of
mandible,mandible,
posterior belly-posterior belly-
mastoid notch ofmastoid notch of
temporal bonetemporal bone
intermediateintermediate
tendon to bodytendon to body
and greater hornand greater horn
of hyoid boneof hyoid bone
depresses the mandible anddepresses the mandible and
raises the hyoid bone. Also, itraises the hyoid bone. Also, it
steadies the hyoid bone duringsteadies the hyoid bone during
swallowing and speakingswallowing and speaking
MylohyoidMylohyoid mylohyoid line ofmylohyoid line of
mandiblemandible
raphe and body ofraphe and body of
hyoid bonehyoid bone
elevates the hyoid bone, floorelevates the hyoid bone, floor
of the mouth and the tongueof the mouth and the tongue
during swallowing and speakingduring swallowing and speaking
StylohyoidStylohyoid styloid process ofstyloid process of
the temporalthe temporal
body of hyoidbody of hyoid
bonebone
elevates and retracts the hyoidelevates and retracts the hyoid
bone, thereby elongating thebone, thereby elongating the

50. EXTRINSIC MUSCLES OF
LARYNX

51. EXTRINSIC MUSCLES OF LARYNX
(contd.)

52. INTRINSIC MUSCLES OF
LARYNX Interarytenoid muscle
 Transverse
 Oblique
 Post. Cricoarytenoid m.
 Lateral cricoarytenoid
m.
 Thyroarytenoid m.
 Cricothyroid m.

53. Muscles Controlling Movements of
the Vocal Cords
IntrinsicIntrinsic
MusclesMuscles
OriginOrigin InsertionInsertion ActionAction
Posterior
cricoarytenoid
posteriorposterior
surface of thesurface of the
lamina of thelamina of the
cricoid cartilagecricoid cartilage
muscular processmuscular process
of the arytenoidof the arytenoid
cartilagecartilage
Abduct vocal cordAbduct vocal cord
Interarytenoid m.,
transverse
posteriorposterior
surface of thesurface of the
arytenoidarytenoid
cartilagecartilage
posterior surfaceposterior surface
of theof the
contralateralcontralateral
arytenoidarytenoid
cartilagecartilage
Closes posteriorCloses posterior
part of rimapart of rima
glottidis byglottidis by
approximatingapproximating
arytenoidarytenoid
cartilagescartilages

54. Muscles Controlling Movements Of
The Vocal Cords
Intrinsic
Muscles
Origin Insertion Action
Lateral Crico-
arytenoid
Lateral part of
upper border of
arch of Cricoid
Muscular
process of
Arytenoid
Adductor of
the vocal
cord.
Crico-thyroid Lower border
and lateral
surface of
Cricoid
Inferior cornu
and lower
border of
Thyroid
cartilage.
Tensor of
Vocal cords

57. MUSCLES CONTROLLING THE
LARYNGEAL INLET
Intrinsic MusclesIntrinsic Muscles OriginOrigin InsertionInsertion ActionAction
Interarytenoid
m., oblique
muscular processmuscular process
of the arytenoidof the arytenoid
cartilagecartilage
posterior surface ofposterior surface of
the contralateralthe contralateral
arytenoid cartilage,arytenoid cartilage,
near its apexnear its apex
draws arytenoiddraws arytenoid
cartilages together,cartilages together,
adducting the vocaladducting the vocal
folds (closure offolds (closure of
glottis)glottis)
Thyroepiglottic inner surface ofinner surface of
the thyroidthe thyroid
cartilage near thecartilage near the
laryngeallaryngeal
prominenceprominence
lateral surface oflateral surface of
the epiglotticthe epiglottic
cartilagecartilage
draws the epiglotticdraws the epiglottic
cartilage downwardcartilage downward

60. MUCOUS MEMBRANE
 Stratified squamous epith.: over vocal cords and
upper part of vestibule of larynx
 Ciliated columnar epith.: remainder of the cavity
 Mucous glands:
 Ventricles and sacculi
 Posterior surface of epiglottis
 Margins of aryepiglottic folds
 Reinke’s layer of connective tissue: No glands and no
lymph vessels

61. NERVE SUPPLY
 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

64. NERVE SUPPLY
 Supplied by Vagus nerve:
 Superior laryngeal n.
Internal branch (sensory) – areas
above the glottis
External branch (motor and sensory)
Motor – Cricothyroid muscle
Sensory – Anterior infraglottic
larynx at level of cricothyroid
membrane

65. ARTERIAL SUPPLY
 Area above vocal cords
 Superior laryngeal
artery
 Area below vocal cords
 Inferior laryngeal
artery

66. VENOUS DRAINAGE
 Upper Larynx
 Superior laryngeal
vein
 Lower Larynx
 Inferior laryngeal
vein

67. LYMPHATIC DRAINAGE
 Supraglottis:-
upper deep cervical
nodes
 Glottis:-
sparse, except for a
small lymph node in the
cricothyroid membrane
delphian node
 Subglottis:-
lower deep cervical and
mediastinal lymph
nodes via prelaryngeal
and paratracheal nodes

68. INDIRECT
LARYNGOSCOPY