Anatomy of larynx

1. ANATOMY OF LARYNX
Dr. Jinu
Department of ENT

2. The larynx extends from the laryngeal inlet to
the inferior border of the cricoid cartilage.

3. • Larynx lies opposite the third to sixth cervical
vertebrae, being a little higher
in women than in
men.
• The infantile larynx
is proportionally
smaller and is more
funnel shaped.

4. Measurements
• Until puberty there is little difference b/w male &
female larynx.
• After puberty:- Male larynx undergoes
considerable increase
In Males In Females
Length 44 mm 36 mm
Transverse diameter 43 mm 41mm
A-P diameter 36 mm 26 mm
Circumference 136 mm 112 mm

5. The framework of the larynx
• Hyoid bone
• 9 Cartilages: –
Connected by
• Joints
• Ligaments
• Membranes
• Moved by
• 8 Muscles(Intrinsic)
• Cavity – Mucous membrane

6. Cartilages
• 3 Paired
• Arytenoid
• Corniculate
• Cuneiform
• 3 Unpaired
• Thyroid
• Cricoid
• Epiglottis

7. HYOID BONE
U-shaped bone

8. Thyroid Cartilage
• Shield shaped, open posteriorly, angulated
anteriorly
• Largest cartilage of larynx
• Protect larynx
• Provide an attachment to vocal cords

13. • The lateral thyrohyoid ligament connects the
tip of the superior cornua of the thyroid
cartilage to the posterior ends of the greater
cornua of the hyoid.
• The ligaments often contain a small nodule of
cartilage, the cartilago triticea

15. On the external surface of each lamina, an oblique
line
curves downwards and forwards from the superior
thyroid tubercle, situated just in front of the root of
the superior horn, to the inferior thyroid tubercle
on the lower border of the lamina.
This line marks the attachment of the
 Thyrohyoid,
Sternothyroid
Inferior constrictor muscles.

18. • A vertical ridge in the midline of the lamina
gives attachment to
longitudinal muscle of the oesophagus
and produces a shallow concavity on each
side for the origin of the
posterior cricoarytenoid muscle.
• The entire inner surface of the cricoid
cartilage is lined with mucous membrane.

19. Of laryngeal inlet

21. • Hyoepiglottic ligament divides epiglottis into
– Suprahyoid Epiglottis
– Infrahyoid Epiglottis

22. Lateral

23. Pre-epiglottic space of Boyer
Anterior surface of infrahyoid epiglottis is
separated from thyrohyoid membrane and
thyroid cartilage by fat filled pre-epiglottic
space.
Pre-epiglottic space invaded by carcinoma of
supraglottic larynx and the base of tongue.

25. Boundaries
Anterior: Upper part of thyroid cartilage and
thyrohyoid membrane.
Superior: Hyoepiglottic ligament.
Posterior: Infrahyoid epiglottis.
Inferior: Thyroepiglottic ligament.
Communication: Laterally it is continuous with
paraglottic space.

29. • Thyroid Hyaline Cartilage
• Cricoid May ossify after 20
• Arytenoids yrs (Male)(T→C→A)
(Except its tip) complete by 65yrs.
• Epiglottis Fibroelastic
• Corniculate They do not ossify
• Cuneiform
• Tip of Arytenoid

30. Arytenoid Gliding-medially & Laterally
closing and opening the post part of
glottis

31. MEMBRANES & LIGAMENTS
Extrinsic Intrinsic
Thyrohyoid Quadrangular membrane
Cricotracheal vestibular ligament
Hyoepiglottic Crico-vocal membrane &
vocal ligament

33. Thyrohyoid membrane
median thyrohyoid ligament 2lateral thyrohyoid ligament
superior cornua of the
thyroid cartilage to the
posterior ends of the
greater cornua of the
hyoid. Small nodule of
cartilage, CARTILAGO
TRITICEA

34. Epiglottic
cartilage to
the body
of hyoid
bone
Lower
border of
cricoid
cartilage
to 1st
tracheal
ring

35. Intrinsic
• Part of Fibro-elastic Membrane
which lies beneath the
mucous membrane of the
larynx.
• The fibro-elastic membrane
is divided into an upper
and lower part by the
laryngeal ventricle.

36. Cricovocal membrane

37. & Cricothyroid membrane

40. Quadrangular membrane

41. Laryngeal Cavity
• From Inlet
of Larynx to
Lower border
of Cricoid
Cartilage
(Lower border
Of 6th cervical
vertebra)

43. Vestibule:
• This region lies between the laryngeal inlet and
vestibular folds.
Boundaries:
• Anterior wall:
– Posterior surface of
epiglottis.
• Lateral sides:
- Aryepiglottic folds .
• Posterior wall:
-Arytenoids.

44. contains vestibular
ligament, a few fibres
of thyroarytenoideus
muscle and mucous
glands.
(true vocal cords).

45. Broyle’s ligament

46. Ventricle (Sinus of larynx) / sinus of
Morgagni:
• This deep elliptical space lies
between
vestibular
and vocal folds.

47. • The submucosa of the ventricle
contains numerous seromucinous
glands.
• The secretions produced by these
exocrine glands provide both
mechanical and immune (lysozyme)
protection for the vocal folds.

48. Laryngeal saccule/ Saccule of Hilton
• At the anterior end of
the ventricle is a
diverticulum
• The saccule (of Hilton) is
lined with mucous
glands, which are
thought to lubricate the
vocal folds

49. • Abnormal dilatation of the saccule results
in an air-filled laryngocele that should be
distinguished
from a mucocele of the saccule (saccular
cyst), which lacks free communication with the
ventricle not air filled

50. CT shows laryngocele

52. • most of the laryngeal foreign bodies are seen
in supraglottic region lying above the vocal
cords.
• Subglottic region (Infraglottic larynx):
• Extends from below the vocal cords to lower
border of cricoid cartilage.

53. Glottis (Rima glottidis):
• This narrowest part of an adult laryngeal
cavity lies between
vocal cords and
arytenoids of the
two sides.

54. Anteroposterior length of glottis is
men (24 mm)
women (16 mm).

55. Pyriform fossa

56. SPACES OF THE LARYNX
Pre-epiglottic space of Boyer:

57. Pre-epiglottic space of Boyer
• Pre-epiglottic space can be invaded by
carcinoma of supraglottic larynx and the base
of tongue.

58. Paraglottic space l Tuckers Space:
It communicates with pre-epiglottic
space (Anteriorsuperioly)
• Boundaries:
Laterally:
Thyroid cartilage and
cricothyroid membrane.
Medial:
Conus elasticus,
Ventricle and quadrangular
membrane.
Posterior:
Anterior mucosa of pyriform
fossa.

59. Paraglottic space l Tuckers Space:
• Growths invading paraglottic space destroy
cricothyroid Membrane
• Ventricle tumors -> spread transglottically
• Vocal cord tumors involving thyroarytenoid
muscle -> subglottic and extralaryngeal region.
• Lateral supraglottic tumors can travel to
subglottic region ->the inner surface of
thyroid.
• Pyriformfossa tumor ->into endolarynx and fix
vocal folds

60. Reinke’s space
• This potential space has scanty subepithelial
connective tissues and lies under the
epithelium of vocal cords.
• It is bounded by–
Above and below: Arcuate lines.
Anterior: Anterior commissure.
Posterior: Vocal process of arytenoids.

61. Layered structure of the vocal fold
• Lamina Propria- 3Layers
1. Superficial-fibrous Substance(Reinkes space)
2. Intermediate –elastic
3. Deep – Collagen fibres
VOCAL LIGAMENT formed
By Intermediate and deep
layer
Body contain Vocalis muscle

62. MUSCLES OF LARYNX
• There are two types of laryngeal muscles
intrinsic (connecting laryngeal cartilages
to each other)
extrinsic (connecting larynx to the
surrounding structures).

63. Intrinsic muscles
They are further divided into two:
1) muscles acting on vocal cords
2) muscles acting on laryngeal inlet.
Vocal cords
Abductors: Posterior cricoarytenoid
Adductors: Lateral cricoarytenoid
Interarytenoid (transverse and oblique
arytenoids)
Thyroarytenoid (external part)
Tensors: Cricothyroid
Relaxers: Vocalis & Thyroarytenoid internal part

64. Cricothyroid
Action: lengthens vocal
folds(tensor)
• Nerve(motor supply) :
Supplied by the
external laryngeal
nerve,a branch of
superior laryngeal
nerve.

65. Posterior cricoarytenoid
• Action: Abduction of
Vocal Cord

67. Interarytenoid
• Transverse
interarytenoid
Action : Adducts vocal
folds
• oblique
interarytenoids
Action : Closes laryngeal
inlet

68. Thyroarytenoid –
Internal part (Vocalis)
• Action : Shortens
vocal folds &
thickness

69. Relaxers of VC: Vocalis and
thyroarytenoid

70. Laryngeal inlet
• Openers:
Thyroepiglottic
(part of thyroarytenoid)
• Closers:
- Interarytenoid
(oblique part)
- Aryepiglottic (posterior
oblique part of
interarytenoid)

71. (1) digastric, (2) stylohoid,
(3) mylohyoid, (4) sternocleidomastoid, (5) thyroidhyoid,
(6)sternothyroid, (7) cricothyroid, (8)
sternohyoid and (9) omohyoid
Omohyoid

73. Extrinsic muscles:
• Secondary elevators: They are attached to the
hyoid bone
Mylohyoid (main)
Digastrics
Stylohyoid
Geniohyoid.

76. Lymphatic Drainage

77. EMBRYOLOGICAL DEVELOPMENT
Structure Source
laryngeal mucosa Endoderm of cephalic part
of foregut
laryngeal cartilages mesenchyme
Epiglottis Hypobranchial eminence
Upper part of body of hyoid bone
Lesser cornua of hyoid bone
Stylohyoid ligament
2nd branchial arch
Lower part of body of hyoid bone
and greater cornua
3rd branchial arch

78. Upper part of thyroid cartilage 4th branchial
arch
lower part of thyroid cartilage,
cricoid, corniculate, and cuneiform 6
th
arch
cartilages
Intrinsic muscles of larynx 6th branchial Arch

79. Infant Larynx VS Adult Larynx
Infant Larynx Adult Larynx
higher in the neck
Voca lcords lie at C3/C4 level
During swallowing go up to C1/C2 level.
Low
Vocal cords lie at C5 level.
Laryngeal cartilages are soft and
collapse easily.
Cartilage undergo ossification
Epiglottis: omega shaped & Floppy Firm and flatter
Arytenoids: large
Thyroid: flat.
Cricoid: The diameter of cricoid is smaller
than glottis
subglottis is the narrowest portion
Glottis is the narrowest portion
Cricothyroid and thyrohyoid spaces: They
are very narrow

80. Infant Larynx Adult Larynx
Size: smaller and has a narrower lumen. Wider lumen
Shape: It is conical and funnel-shaped column shaped
Submucosal tissue: It is thick and loose
and becomes easily
edematous in response to trauma or
inflammation

81. Infant Adult

82. Adult Larynx Infant Larynx

83. Applied anatomy