The larynx houses the vocal cords, and manipulates pitch and volume, which is essential for phonation. It is situated just below where the tract of the pharynx splits into the trachea and the esophagus.

1. Anatomy of Larynx
Dr Mathew Joseph MBBS, MD(AIIMS), BCC(Palliative Medicine)
Assistant Professor
Department of Anatomy
Amala Institute of Medical Sciences, Thrissur

2. Larynx

3. Larynx:
• A hollow musculao-ligamentous structure with cartilagenous framework.
• Cavity is continuous below with the trachea, and above opens into the pharynx.
• Valve (or sphincter) to close the lower respiratory tract (protection)
•Phonation
•Respiration
•Deglutition
•
•

5. Extent:
• Root of tongue – Trachea
• Front of 3,4,5,6 cervical vertebrae

16. • Three large unpaired cartilages (Cricoid,
Thyroid and Epiglottis)
• Three pairs of smaller cartilages (Arytenoid,
Corniculate, and Cuneiform)
• A fibroelastic membrane and numerous
intrinsic muscles
Laryngeal Cartilages

17. • Leaf-shaped cartilage.
• Attached by its stem to the posterior aspect of
the thyroid cartilage by Thyro-epiglottic ligament.
• Projects posterosuperiorly.
• Its upper margin is behind the pharyngeal part of
the tongue.
• Inferior half of the posterior surface of the
epiglottis is raised slightly to form an epiglottic
tubercle.
Epiglottis

19. • Largest of the laryngeal
cartilages.
• Formed by joining of a right and a
left lamina anteriorly as the
laryngeal prominence (Adam’s
apple ).
• Widely separated posteriorly.
Thyroid cartilage

20. • The angle between the two laminae
is more acute in men (900) than in
women (1200) so the laryngeal
prominence is more apparent in
men than women.
Thyroid cartilage

23. • Inferior of the laryngeal cartilages
and completely encircles the
airway.
• Shaped like a ‘signet ring’ with a
broad lamina of cricoid cartilage.
• C6
• Foundation stone
Cricoid cartilage

25. Pyramidal-shaped cartilages.
Arytenoid cartilage

26. • Base is concave and articulates with the
sloping articular facet on the lamina of
cricoid cartilarge.
• Apex articulates with a corniculate
cartilage.
• Medial surface of each cartilage faces the other.
• Anterolateral surface has two depressions
for muscle (vocalis) and ligament
(vestibular ligament) attachment.
Arytenoid cartilage

27. • Elongated Anterior angle is vocalis process for
the vocal ligament attachment.
• Lateral angle is muscular process for
attachment of the posterior and lateral crico-
arythenoid muscles.
Arytenoid cartilage

28. • Corniculate cartilages articulate with the apices of
the arytenoid cartilage.
• Corniculate apices project posteromedially towards
each other.
• Cuneiforms are suspend in the part of the
fibroelastic membrane- aryepiglottic membrane.

29. • Thyroid, Cricoid and Basal parts of A
rytenoid are
composed of Hyaline C
artilage – Ossify after 25
• Apex of Arytenoid and All other are E
lastic
Cartilage

30. Laryngeal Joints

31. Crico-thyroid joint
• The cricothyroid joints enable the
thyroid cartilage to move forward and
tilt downwards on the cricoid
cartilage (effectively lengthens and
puts tension on the vocal ligaments).
Crico-thyroid Joint

32. • Enable the arythenoid cartilages to
slide away or towards each other and to
rotate so that the vocal process pivot
either towards or away from the midline
(abduct and adduct the vocal ligament).
Crico-Aretynoid Joint

33. Laryngeal Ligaments

34. •Thyrohyoid membrane
•Hyo-epiglottic ligament
•Cricotracheal ligament
• Upper Quadrangular Ligament
•Cricothyroid Ligament
(Cricovocal And Cricothyroid
Membrane)
Extrinsic ligaments Intrinsic ligament

35. • Is attached to the arch of cricoid cartilage
and extends superiorly - Thyroid cartilage
anteriorly and vocal process posteriorly.
• The free margin of this ligament is
thickened to form the vocal ligament,
which is under the vocal fold (true ‘vocal
cord’) of the larynx.
• Is also thickened anteriorly in the midline
to form a distinct median cricothyroid
ligament.
Cricothyroid Ligament

36. • Run between the lateral margin of the
anterolateral surface of the arytenoid
cartilage on the same side to epiglottis
superiorly
• Its free lower margin is thickened to form
the vestibular ligament under the
vestibular fold (false ‘vocal cord’).
Quadrangular Membrane

37. Vestibular Ligament
Vestibular ligament is attached
posteriorly to the arytenoid
cartilage and anteriorly to the
thyroid angle just superior to the
attachment of the vocal ligament.

38. • Tubular in shape.
• Lined by the mucosa.
• Opens superiorly (laryngeal inlet) into the anterior aspect of the pharynx
just below and posterior to the tongue.
• Opens inferiorly into the lumen of trachea.
• Laryngeal inlet can be closed by downward movement
of epiglottis whereas the inferior opening is continuously open.
• Wall of laryngeal cavity:
➢Lateral wall: aryepiglottic folds.
➢Anterior border: mucosa covering the superior margin of the
epiglottis.
➢Posterior border: interarytenoid notch (between the two corniculate
tubercles).
Cavity of the larynx

40. • Two pairs of mucosal fold (vestibular and vocal folds) divide the cavity into three major
regions;
1. Vestibuleis (upper chamber) between the laryngeal inlet and the vestibular
ligament.
2. Ventricle (middle chamber) is between the vestibular folds above and the vocal folds
below.
3. Infraglottic space(inferior chamber) is between the vocal folds and the inferior opening
of the larynx.
Laryngeal Cavity

42. • Produce an expanded trough-shaped space.
• Larygeal saccule is an elongate tubular
extension of each ventricle projects
anterosuperior between the vestibular fold and
thyroid cartilage.
• Within the walls of the saccule are numerous
mucous glands which secrete the mucus to
lubricate the vocal folds.
Laryngeal Ventricles and Saccules

43. • Triangular-shaped opening.
• Between the two adjacent vestibular
folds at the entrance to the middle
chamber of the laryngeal cavity.
• Its apex is anterior.
• Its base is formed by the posterior
wall of the laryngeal cavity.
Rima Vestibuli

44. • Between the two adjacent vocal folds.
• Separates the middle chamber above
from the infraglottic cavity below.
• It base is formed by the fold of mucosa
(inter-arytenoid fold) at the bottom of
the inter-arytenoid notch.
Both the rima glottidis and the rima vestibuli
can be opened and closed by movement of the
arytenoid cartilages and associated fibro-
elastic membrane.
Rima Glottidis

45. • Adjust tension in the vocal ligaments.
• Open and close the rima glottidis.
• Control the inner dimensions of the
vestibule.
• Close the rima vestibuli.
• Facilitate closing of the laryngeal inlet.
Function of Intrinsic Muscles

46. • Acting on the cricothyroid and crico- arytenoid joints.
• Adjusting the distance between the epiglottis and
arytenoid cartilage.
• Pulling directly on the vocal ligament.
• Forcing soft tissues associated with the quadrangular
membranes and vestibular ligaments toward the midline.
Action of Intrinsic Muscles

48. • Fan-shaped muscles.
• Attached to the arch of the cricoid cartilage and
to the thyroid cartilage.
• Two parts; oblique and straight.
• Oblique partruns in a posterior direction from
the arch of the cricoid cartilage to the inferior
horn of the thyroid cartilage.
• Straight partruns more vertically from the arch
of the cricoid cartilage to the posteroinferior
margin of the thyroid lamina.
Cricothyroid Muscles

49. • Move the cricothyriod joints.
• Pull the thyroid cartilage forward and rotate it down
relative to the cricoid cartilage-lengthen the vocal folds.
• Only one intrinsic (lies outside) muscles innervated by
the superior laryngeal branches of the vagus nerve (CN
X).
• All other intrinsic muscles are innervated by the
recurrent laryngeal branches of the vagus nerves.
Cricothyroid Muscles

50. •
• Originate from shallow depression
on the posterior surface of the lamina
of cricoid cartilage.
• Run superolaterally to converge on
the muscular processes of the
arytenoid cartilage.
• Abduction and externally rotate the
arytenoid cartilage to open the rima
glottidis.
• Innervated by Recurent laryngeal
branches of the vagus nerve (CN X).
Posterior Crico-Arytenoid Muscle

51. • Originates from the upper surface of the
arch of the cricoid cartilage.
• Runs posterosuperiorly to insert on the
muscular process of the arytenoid cartilage.
• Adduct and internally rotate the arytenoid
cartilage- adducted vocal folds with an open
air channel posteriorly between adjacent
arytenoid cartilages.
• Innervated by the Recurrent laryngeal
branches of the vagus nerve (CN X).
Lateral Crico-Arytenoid Muscles

52. • Is a single muscle.
• Spans the distance between adjacent lateral
margins of the arytenoid cartilages and
covers the posterior surfaces of these
cartilages.
• Is innervated by the Recurrent laryngeal
branches of the vagus nerve (CN X).
Transverse Arytenoid Muscle

53. Oblique arytenoid muscles
• Pair of muscles, runs from the posterior surface of
the muscular process of one arytenoid cartilage to the apex of
the arytenoid cartilage on the other side.
• Some fibers of this muscle continue laterally around the
margin of the arytenoid cartilage and into the aryepiglottic
fold to continue as part of aryepiglottic muscle.
• Can narrow the laryngeal inlet by constricting the distance
between the arytenoid cartilage and the epiglottis.
• Innervated by the recurrent laryngeal branches of the
vagus nerve (CN X)

54. • Are elongate muscles lateral to and running
parallel with each vocal ligament.
• Attaches posteriorly to the lateral surface of
the vocal process and adjacent depression on
the anterolateral surface of the arytenoid
cartilage.
• Insert anteriorly along the length of the vacal
ligament to the thyroid angle.
• Adjust tension in the vocal folds.
• Innervated by the recurrent laryngeal branches
of the vagus nerve (CN X).
Vocalis

55. • Are broad flat muscles lateral to the fibro-elastic
membrane of the larynx and the laryngeal
ventricles and saccules.
• Run from a vertical line of origin on the lower half
of the thyroid angle and adjacent external surface
of the cricothyroid cartilage.
• Some of the fibers may continue into the
aryepiglottic fold and reach part of thyro-epiglottic
muscle.
Thyro-Arytenoid Muscles

57. • Is an elaborate sphincter for the lower respiratory
tract.
• Provides a mechanism for producing sounds.
• Adjusts the size of the ventricle cavity result from
changes in the dimensions of the rima glottidis, rima
vestibuli, vestibule, and the laryngeal inlet.
• This changes result from the muscle actions
and laryngeal mechanics.
Functions of the Larynx

58. During Quiet Respiration
The laryngeal inlet, vestibule, rima
vestibule and rima glottidis are open.
The arytenoid cartilages are abducted.
The rima glottidis in triangular shaped.

59. • The arytenoid cartilage are rotated laterally,
mainly by action of the posterior crico-
arytenoid m.
• As a result, the vocal folds are abducted,
and the rima glottidis widens into a
rhomboid shape, which effectively
increases the diameter of the laryngeal
airway.
During Force Respiration

60. • Arytenoid cartilages and vocal folds are
adducted and air is forced through the
closed rima glottidis.
• This action causes the vocal folds to
vibrate against each other and produce
sounds, which can then be modified by
the upper parts of the airway and oral
cavity.
• Tension in the vocal folds can be adjusted
by the vocalis and cricothyroid muscle.
Phonation

61. • Occurs when air is retaind in the thoracic
cavity to stablize the trunk, for example
during heavy lifting, or as part of the
mechanism for increasing intra- abdominal
pressure.
• During effort closure, the rima glottidis is
completely closed, as is the rima vestibuli
and lower parts of the vestibule.
• The result is to completely and forcefully
shut the airway.
Effort Closure

62. During Swallowing
• The rima glottidis, the rema vestibuli and vestibule are closed and laryngeal
inlet is narrowed.
• The larynx is moved upward and forward causing the epiglottis to swing
downward towards the laryngeal inlet.
• All the actions together prevent solids and liquids from entering into the
airway and facilitate their movement through piriform fossa to esophagus.

63. • Is a procedure in which a hole is made in the trachea and
a tube is inserted to enable ventilation when the foreign
body obstruct to the larynx.
• A small transverse incision is placed in the lower third of
the neck anteriorly (at level 2ndand 3rdtracheal rings),
deviates the strap muscle laterally and divides the isthmus
of the thyroid gland.
• Pateint with long-term tracheostomies are unable to
vocalize because no air is passing through the vocal
cords.
Tracheostomy

64. • Superior laryngeal a. Originates from the
Superior thyroid a. and accompaneis the
internal branch of the superior laryngeal nerve
through the thyrohyoid membrane.
• Inferior laryngeal a. Originates from the Inferior
Thyroid branch of thyrocerical trunk, together
with the recurrent laryngeal n.
Arterial Supply

65. • Superior laryngeal veins drain into
superior thyroid veins, which in
turn drain into the internal
jugular vein.
• Inferior laryngeal veins drain into
inferior thyroid veins, which drain
into the left brachiocephalic veins.
Venous drainageof larynx

66. • Drain regions above and below the vocal folds
• Those above the vocal fold follow the superior laryngeal a. and terminate in deep
cervical nodes associated with the bifurcation of the common carotid a.
• Those below the vocal folds drain into deep nodes associated with the inferior thyroid a.
or with nodes associated with the front of the cricothyroid ligament or upper trachea.
Lymphatic Drainage

67. • Sensory and motor is supplied
by 2 branches of vagus nerve:
1. Superior laryngeal nerve
2. Recurrent laryngeal nerve
Innervation of Larynx

68. Superior Laryngeal Nerve
• Originate from the inferior vagal ganglia.
• Divide into internal and external branches just above the
level of the superior horn of the hyoid bone.
• External branch (external laryngeal br.) decends along
the lateral wall of the pharynx to supply and penetrate
the inferior constrictor of the pharynx and ends by the
supplying the cricothyroid muscle.
• Internal branch (internal laryngeal nerve) passes
anteroinferiorly to penetrate the thyrohyoid membrane.
• (it is mainly sensory and supplies the laryngeal cavity
above level of the vocal folds.)

69. Recurrent Laryngeal Nerves
•
• Sensory to the laryngeal cavity
below the level of the vocal folds.
• Motor to all intrinsic muscles of the
larynx except for the cricothyroid.
• Left recurrent laryngeal n.
originates in the thorax.
• Right recurrent laryngeal n.
originates in the root of neck.
• Enter the larynx deep to the margin
of the inferior constrictor.

70. • Sinus of morgagni [ventricle of
larynx] ?
• Singer’s nodule ?
• Piriform fossa ?