Nice Pictorial presentation to understand the anatomy of larynx. I also enumerated the spaces of larynx & action of laryngeal muscles in detail.

1. Anatomy of Larynx
Dr Utkal Mishra
PG (ENT)
VSS MEDICAL COLLEGE, BURLA

2. Introduction
 Larynx (voice box) is situated in front of hypopharynx
opposite 3rd to 6th cervical vertebra
 It extends from Laryngeal inlet to Inferior border of
cricoid cartilage.
 Primary function of larynx is protection of lower airway
from food particles and secretion of oropharynx.

3. Embryology
 Larynx develops from - Cranial part of Laryngotracheal
groove (Ventral aspect of foregut) during 4th wk of
IUL.
 Most of the anatomical characteristics of larynx develop
by the 3rd month of fetal life.
 The larynx descends in the neck to achieve its final position
at vertebrae C3-C6 by age - 6 years.

4. Development of laryngeal cartilages
Name of the cartilage Developed from
 Thyroid cartilage Upper part- 4th arch
Lower part – 6th arch
 Epiglottis Hypobranchial eminence
 Arytenoids 6th arch cartilage
 Corniculate 6th arch cartilage
 Cricoid 6th arch cartilage

5. Laryngeal Framework
 Laryngeal Cartilages
 Laryngeal Joints
 Laryngeal Ligaments & Membranes.
 Laryngeal Muscles
 Cavity of Larynx

6. Laryngeal Cartilages
 9 in no.
 3 unpaired – Thyroid
Cricoid
Epiglottis
 3 paired – Arytenoid
Corniculate
Cuneiform

7. Thyroid Cartilage
Superior
tubercle
Thyroid
Notch
Oblique Line

8. Cricoid Cartilage

9. Epiglottis

10. Arytenoid Cartilage

11. Corniculate & Cuneiform

12. Laryngeal Joints
 2 in no.
 Cricoarytenoid joint
 Cricothyroid joint

13. Cricoarytenoid joint

14. Cricothyroid joint

15. Laryngeal Ligaments & Membranes
 Extrinsic - Thyrohyoid Membrane
Cricotracheal Membrane
Hyoepiglottic Membrane
 Intrinsic - Cricovocal Membrane
Quadrangular Membrane
Cricothyroid Ligament
Thyroepiglottic Ligament

16. Extrinsic Ligaments

17. Cricovocal & Quadrangular Membrane

18. Muscles of Larynx
INTRINSIC MUSCLES -
 Acting on Vocal cords –
Only Abductor - Postr. Cricoarytenoid
Adductors - Lateral Cricoarytenoid
Interarytenoid (Transv.)
Thyroarytenoid
Tensors - Cricothyroid
Vocalis
 Acting on Laryngeal Inlet –
Openers - Thyroepiglottic
Closers - Aryepiglottic
Interarytenoid (oblique)
EXTRINSIC MUSCLES –
Elevators- Stylopharyngeus Depressors- Sternohyoid
Salpingopharyngeous Sternothyroid
Palatopharyngeous Omohyoid
Thyrohyoid

19. Postr. Cricoarytenoid M.
 Only abductor of vocal cord
 Origin- Posterior surface of cricoid lamina
 Insertion- Muscular process of arytenoid
 Action- vocal cord abduction
 Nerve - RLN

20. Latr. Cricoarytenoid M.
 Origin- Superior border of lateral part of
the arch of the cricoid cartilage
 Insertion- Muscular process of arytenoid
 Action- Vocal cord adduction
 Nerve - RLN

21. Interarytenoid M.
 Oblique/ transverse part
 Adducts the vocal cord
 Oblique part continues as
aryepiglotticus
 Aryepiglotticus have a
sphincter action on AE fold
during swallowing

22. Thyroarytenoid M.
 Origin- Angle of thyroid cartilage
 Insertion- Anterolatr. surface of arytenoids
 Action- Drags arytenoid forward
 Adducter of vocal cord
 Internal part of Thyroarytnoid M. - Vocalis

23. Cricothyroid M.
 Tensor of vocal cord
 Origin- Cricoid arch
 Insertion- Infr. border thyroid cartilage
 Action- Tilts thyroid forward & cricoid
backward -stretches vocal cord
 Makes vocal cord thinner & longer - ↑ pitch
 Nerve - External branch of SLN

24. Cavity of Larynx
 It starts from Layngeal Inlet &
ends at lower border of cricoid cartilage.
 Divided into 3 parts by vestibular & vocal folds
1. Vestibule
2. Ventricle
3. Subglottis

25. Cavity of Larynx (cont.)
 Vestibule – Extends from laryngeal inlet to
vestibular folds
Antr. wall - Postr. surface of
Epiglottis
Latr. Wall – Aryepiglottic folds
Postr. Wall – Arytenoids
 Ventricles – Space between vestibular & vocal
folds
- Extends above to form Saccule
- Mucous glands in saccule
lubricates vocal cords
 Subglottis – Extends from vocal cords to
lower border of cricoid.

26. Glottis
 Elongated space between vocal cords anteriorly & vocal process
& base of arytenoids posteriorly.
 Anteroposteriorly - 24mm in male & 16 mm in female.
 Anterior 3/5th - Membranous (Phonatory glottis)
 Posterior 2/5th - Cartilagenous (Respiratory glottis)

27. Vocal Cords
Histologicaly the vocal
cord contains 5 layers
1. Epithelial layer
2. Superficial LP
3. Intermediate LP
4. Deep LP
5. Vocalis Muscle

28. Mucous Membrane of Larynx
 Pseudo stratified ciliated columnar epithelium
 Except - Upper ½ of postr. Surface of Epiglottis
Upper part of Aryepiglottic fold
Postr. Glottis
Vocal Cords
which are covered by – Nonkeratinizing Stratified
Squamous Epithelium

29. Spaces within Larynx
 3 in no.
 Preepiglottic Space of Boyer
 Paraglottic Space
 Rienke’s Space

30. Pre-epiglottic Space of Boyer
 Boundary -
Antr.ly – Thyrohyoid Membrane
Hyoid bone
Postr.ly- Epiglottis
Supr.ly – Hyoepiglottic Ligament
 Contents – Fat, Areolar tissue ,
Lymphatics
 It is continous laterally with
Paraglottic space.

31. Paraglottic Space
 Bounded
 Laterally – Thyroid Cartilage
 Medially – Conus Elasticus
- Quadrangular
Membrane
 Posteriorly – Mucosa of
Pyriform Fossa
It encompasses the laryngeal
ventricle & saccule
Paraglottic
Space

32. Rienkes Space
 It is the space underlying
Epithelium of vocal cords
 Bounded
 Above & Below – Arcuate
Lines
 In front - Anterior
Comissure
 Behind – Vocal process of
Arytenoid

33. Nerve Supply Of Larynx
 Motor –
 All Intrinsic M. – Rec. Laryngeal N.
 Except Cricothyroid – Extn. Br. Of
Supr. Laryngeal N.
 Sensory –
 Above Vocal Cords – Internal Br. Of
Supr. Laryngeal N.
 Below Vocal Cords – Rec. Laryngeal N.
 Rec. Laryngeal N. arises from trunk
of Vagus.
 Supr. Laryngeal N. arises from
Inferior Ganglion of Vagus.

34. Laryngeal Vasculature

35. Lymphatic Drainage
 The part of the larynx above the vocal folds is drained by vessels
accompanying the superior laryngeal vein to UPPER DEEP
CERVICAL NODES
 Below the vocal folds drains with the inferior vein, into
PRE-LARYNGEAL and PRE-TRACHEAL nodes.
 The vocal folds are devoid of lymphatics. (Water- Shed zone)

36. Paediatric Larynx
 Positioned high in neck – C3 - C4
 Cartilages soft & collapsible
 Submucosal tissue are loose
 Small & Conical
 Narrowest portion is subglottis