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
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)
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.
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