Larynx anatomy and physiology

Larynx is important for protection of airway, phonation and stablize the chest for

1. ANATOMY & PHYSIOLOGY OF LARYNX BRIG ANWAR UL HAQ ENT SPECIALIST

2. Laryngeal cartilages Laryngeal M embranes L a r y n g ea l m u s c l e s f u n c t i o n 3 S ub di v i s io n s o f l a ry n x Nerve supply of larynx Functions of larynx CONTENTS

3. A n a t o m y o f l a ryn x Rigid skeleton cartilages, muscles ligaments m embranes Exten sion from hyoid bone above to cricoid cartilage below Opposite to C3 to C6 Laryngeal crepitus : Normally present Absent in post-cricoid carcinoma

4. L a ryng e a l c a r t i l a g e s 3 unpaired 3 paired cartilages Unpaired: Thyroid Cricoid Epiglottis Paired: Arytenoid Cuneiform ( Wrisberg) Corniculate (Santorini)

5. Histological types of laryngeal cartilages Elastic: (little or no calcification) Epiglottis Corniculate Cuneiform Apex of arytenoid Hyaline (calcify as age advances) Thyroid Cricoid Remaining arytenoid Ossification B egins by 25 yrs Completed by 60 yrs

6. Thyrohyoid membrane: Cricothyroid membrane: cricothyro ido tomy done though this membrane • Cricoid cartilage: only rigid & complete ring among the cartilages forming larynx and trachea

7. Cartilages (anterior )

8. Cartilages (posterior)

9. Laryngeal Membranes (I ). Extrinsic membranes : Thyrohyoid membrane Cricothyroid membrane Cricotracheal membrane (II ). Intrinsic membranes : Cricovocal membrane  forms vocal ligament Quadrangular membrane  forms the vestibular ligament

10. L a ryn x ( s a g i t t a l s e c t i o n )

11. Larynx (Coronal Section)

12. NPL(Nasopharyngolaryngoscopy)

13. V o c a l f ol d

14. Pediatric Larynx Vs Adult larynx Subglottis is the narrowest part – may cause stridor easily Loose submucosal tissues (swell up easily ) may cause croup Positioned high (C3-C4) Soft cartilages  collapse easily - Laryngomalacia

15. S ub d iv i si o n s o f L a ry n x A. Supraglottis: laryngeal inlet to apex of ventricle B. Glottis: apex of ventricle to 1cm below C. Subglottis: lower glotti s border to lower cricoid

16. Sub Sites A. Supraglottis : 1.Epiglottis 2. AE fold 3. False Vocal Cords 4. Ventricle B. Glottis: 1.True Vocal Cords 2. Anterior commissure 3. Posterior commissure C. Subglottis

17. Intrinsic Muscles A. Acting on vocal cords 1. Abduction Posterior crico-arytenoid Adduction Lateral cr ico -arytenoid Transverse arytenoid ( inter- arytenoid) Thyro -arytenoid 2. Tension + lengthening Cricothyroid 3. Relaxation + shortening Vocalis ( internal part of thyroarytenoid )

18. B. Acting on laryngeal inlet Opener  Thyro-epiglottic (part of thyroarytenoid) Closer  Inter-arytenoid ( oblique part) Ary- E piglottic (Posterior oblique part of inter - arytenoid )

19. E x t rins i c l a ry n g e a l musc l e s Elevators of larynx Primary elevators Stylo-pharyngeus Salpingo-pharyngeus Palato-pharyngeus Digastric S econdary elevators Mylohyoid Stylohyoid Geniohyoid Depressors of larynx ( strap muscles of the neck ) Sternohyoid ,Sternothyroid , thyrohyoid ,Omohyoid

20. Posterior cricoarytenoid

21. Lateral cricoarytenoid

22. Transverse Inter-arytenoid

23. Cricothyroid

24. Oblique Inter-arytenoid

25. Mucous Membrane 1.Stratified squamous epithelium 2.Pseudostratified ciliated columnar ( respiratory) epithelium

26. N e rv e S up p l y Superior Laryngeal Nerve ( SLN ): Internal: Sensory supply to supraglottis & glottis External: Motor supply to cricothyroid muscle Recurrent Laryngeal Nerve(RLN): Sensory supply to subglottis Motor supply to all intrinsic muscles except cricothyroid

27. B l o o d S u p p l y Arterial supply: Laryngeal branch of superior & inferior thyroid artery Venous drainage : Superior thyroid vein  internal jugular vein Inferior thyroid vein  innominate vein

28. Lymphatic Drainage Supraglottis: Upper deep cervical nodes Subglottis: Pretracheal lower deep cervical nodes Glottis : has no lymphatics

29. Functions of Larynx Protection of lower airway: Primary function Closure of larynx: Three tier mechanism Cough reflex Phonation (voice production): Secondary function Respiration 4.Chest fixation by glottic closure: Coughing Micturition Defecation

30. DUGLITATION

31. SWALLOWING

32. Phonation

33. OPERA SINGING

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