anatomy of larynx

1. ANATOMY OF LARYNX
Dr.R.Malarvizhi MS (ENT), DLO

2. The VOICE BOX
• Lies in front of hypopharynx
• Opp 3-6th cervical vertebra
• Moves vertically and anteroposterior
direction during swallowing

3. Embrology

4. Laryngeal framework
• Cartilages
• Muscles
• Membranes
• Joints

5. Laryngeal Cartilages
Paired
• Arytenoid
• Cuneiform/Wrisberg
• Corniculate / Santorini
• Epiglottis
• Thyroid
• Cricoid

6. Laryngeal Cartilages
Hyaline
• Thyroid
• Cricoid
• Most of Arytenoid
Fibroelastic
• Epiglottis
• Corniculate
• Cuneiform
• Tip of Arytenoid

7. Thyroid Cartilage
• Largest
• 2 alae and 2 pairs of
superior and inferior
cornua
• Two alae meet
anteriorly forming an
angle
– Male 90 °
– Female 120°
• Vocal folds are
attached to the middle
of thyroid angle

8. Cricoid Cartilage
• ONLY complete ring
• Anteriorly narrow
arch and posteriorly
broad lamina

9. Arytenoid Cartilage
• Paired
• Pyramidal shape
• Base articulates with
cricoid cartilage
• Muscular process
attached with intrinsic
laryngeal muscles
• Vocal process attachment
to vocal fold
• Apex supports corniculate
cartilage

10. Epiglottis cartilage
• Leaf shaped
• Yellow, elastic
• Forms anterior wall
of larynx
• Covers inlet
• Attached to hyoid by
hyoepiglottic
ligament – infra
hyoid and
suprahyoid
epiglottis
• Petiole

11. Corniculate and Cuneiform
• Paired
• Corniculate-
articulates with
apex of
arytenoid
• Cuneiform – rod
shaped,
situated in
aryepiglottic
fold, passive
support to fold

12. Joints
• Cricoarytenoid joint-
– Synovial
– Base of arytenoid, a facet, upper border of cricoid lamina
– 2 movements-
• Rotatory- arytenoid cartilage moves around vertical axis-
abducting and adducting vocal fold
• Gliding – one arytenoid glides towards or away from other- closing
or opening glottis
• Cricothyroid joint
– Synovial,
– Inferior cornua of thyroid cartilage with facet on cricoid
cartilage

13. Laryngeal Membranes
Extrinsic
• Thyrohyoid-
– pierced by superior
laryngeal vessles
– internal laryngeal nerve
• Cricothyroid
• Cricotracheal
Intrinsic
• Cricovocal (CONUS
ELASTICUS)
• Quandrangular

16. Muscles of Larynx
Intrinsic
• Act on vocal folds
– Abductors
• Posterior Cricoarytenoid
– Adductors
• Lateral Cricoarytenoid
• Interarytenoid (Transverse)
• thyroarytenoid
– Tensors
• Cricothyroid
• Vocalis
• Act on laryngeal inlet
– Openers
• Thyroarytenoid (Thyroepiglottic)
– Closers
• Interarytenoid (Oblique)
• Aryepiglottic (posterior oblique
part of interarytenoid)
Extrinsic
• Elevator
– Primary (THYROID)
• Stylopharyngeus
• Salpingopharyngeus
• Palatopharyngeus
• Thyrohyoid
– Secondary (HYOID)
• Mylohyoid
• Digastric
• Stylohyoid
• Geniohyoid
• Depressors
– Sternohyoid
– Sternothyroid
– Omohyoid

22. Cavity of Larynx
• Starts at inlet communicating with pharynx
• Ends lower borders of cricoid cartilage
continuous with lumen of trachea
– Inlet
– Vestibule
– Ventricle
– Subglottic space
– Vestibular and vocal folds
– Rima glottidis

23. • Inlet
– Oblique opening
– Anteriorly by free margin of epiglottis,
aryepiglottic folds laterally and posteriorly by
interarytenoid fold
• Vestibule
– Between laryngeal inlet and vestibular folds
– Anteriorly by posterior surface of epiglottis,
laterally by aryepiglottic folds and posteriorly
by mucous membrane over arytenoids

24. • Ventricle (Sinus of larynx)
– Deep elliptical space
– Between vestibular and vocal folds
– Extending short distance above and lateral to
vestibular folds
– Saccule – diverticulum of mucous membrane
starting from anterior part of ventricular cavity
and extends between vestibular folds and
lamina of thyroid cartilage (oil can of larynx)
• Laryngocele

25. • Subglottic space
– Extends from vocal fold to lower border of cricoid cartilage
• Rima glottidis
– Glottis proper; elongated space between vocal folds
anteriorly & vocal process and base of arytenoids
posteriorly
– Anteroposteriorly
• 24 mm in Males
• 16 mm in Females
– Narrowest part
– Size and shape varies
– Antr 2/3rd membranous cords and Postr 1/3rd by vocal
process of arytenoids

29. VOCAL FOLDS
• Vocal folds (True)
– Pearly sharp bands
– Middle of thyroid angle to vocal process of
arytenoids
– Vocal ligament – true upper edge of
cricovocal membr covered by closely bound
mucous membrane with scanty subepithelial
connective tissue
– Multilayered

30. VOCAL FOLDS continued
• 5 layers (medial to
lateral)
– Stratified squamous
epithelium
– Superficial layer-
Lamina propria
– Middle layer- Lamina
propria
– Deep layer- Lamina
propria
– Vocalis muscle

31. • Vestibular folds (False)
– Fold of mucous membr extending
anteroposteriorly across laryngeal cavity
– Vestibular ligament, few fibres of
thyroarytenoid muscle and mucous glands

33. Mucous Membrane of
Larynx
• Lines larynx
• Loosely attached except over posterior surface of
epiglottis, vocal folds and corniculate and cuneiform
cartilages
• Ciliated columnar epithelium
– Except over vocal folds and upper part of vestibule-
Stratified squamous
• Mucous glands
– All over
– More over posterior surf epiglottis, postr part of aryepiglottic
folds and saccules
– NONE OVER VOCAL FOLDS

34. Lymphatic Drainage
• Vocal folds / glottis- nil
• Supraglottic- drained by lymphatics
piercing thyrohyoid membrane- reach
upper deep cervical lymph nodes
• Infraglottic – drained by lymphatics
piercing cricothyroid membrane –
pretracheal and prelaryngeal nodes-
lower deep cervical nodes and
mediastinal nodes

35. Nerve supply
• Motor
– All by Recurrent laryngeal nerve
– Except CRICOTHYROID- External branch
of superior laryngeal nerve
• Sensory
– vocal folds
• Above – internal branch of superior laryngeal
nerve
• Below – recurrent laryngeal nerve

36. Nerve supply
• Recurrent laryngeal nerve
– Right – from VAGUS, level of subclavian
artery hooks around it and then ascends
b/w trachea and esophagus
– Left from VAGUS, level arch of aorta in
mediatinum, loops around it and ascends
in neck of tracheo- osophageal groove
• Longer course

37. Nerve supply
• Superior laryngeal nerve
– Inferior ganglion of VAGUS
– Descends behind ICA and at level of
greater cornua of hyoid divides 2 branches
• External
• Internal

38. Galen’s Anastamoses
• Recurrent laryngeal nerve and Superior
laryngeal nerve give off branches and
anastamose with each other –Galen’s
anastamoses

39. SPACES
• Pre- epiglottic space
– Boyer
– Filled with fat , areolar
tissue and some
lymphatics
– Anteriorly- upper part of
thyroid cartilage
– Superiorly- hyoepiglottic
ligt
– Posteriorly – infrahyoid
epiglottis and
quadrangular membrane
– Laterlly – continuous
paraglottic space

40. Spaces
• Paraglottic Space
– Tucker
– Continuous with Boyer’s
space
– Anteriorly and laterally-
thyroid cartilage
– Supero medially-
quadrangular membrane
– Inferomedially – conus
elasticus
– Posteriorly- mucous
membrane over pyriform
fossa

41. Spaces
• Reinke’s space
– Potential space between epithelium of vocal fold
and vocal ligt
– Superficial layer of lamina propria
– Bound anteriorly by Broyles’ ligt ; posteriorly by
arytenoid cartilage and inferiorly by vocal ligt

42. Blood supply
• Superior thyroid artery (branch of ECA)
• Inferior thyroid artery (branch of
Thyrocervical trunk)

43. SUBDIVISIONS OF
LARYNX
• Supraglottis
– From infrahyoid portion of epiglottis to
vocal folds
• Glottis
– Vocal folds, anterior and posterior
commissures
• Subglottis
– Below vocal folds to lower border of cricoid
cartilage (5mm )

44. Adult vs Pediatric

46. Physiology
• Protection of lower airways
• Phonation
• Respiration
• Fixation of chest

47. Theories of phonation
Myoelastic Aerodynamic
theory Cover body theory