Anatomy of the Larynx.pptx

Anatomy of the larynx

1. ANATOMY OF LARYNX

2. OUTLINE Anatomy Embrology of Larynx Clinical correlation

3. ANATOMY OF THE LARYNX INTRODUCTION Hollow tubular structure situated above the trachea. Extends from the laryngeal inlet to the inferior border of the cricoid cartilage . Opposite the third to sixth cervical vertebrae, this level may be some what higher in women and children than in men After puberty the antero posterior diameter of larynx virtually doubles in males .

4. Embryology Development of laryngeal cartilage Name of the catilage Developed from Thyroid Ventral end of 4 th arch Arytenoids 6 th arch Corniculate 6 th arch Epiglottis Hypobrachial eminence Cricoid &Trachea 6 th brachial arch

5. The larynx is divided anatomically in to : supra glottis . glottis . And sub glottis . By the falls and true vocal cords.

6. ANATOMICAL DIVISION OF THE LARYNX

7. The supraglottis consists of superiorly the epiglottis and aryepiglottic folds as they sweep down to the arytenoids. Its lower border is the ventricular bands (false cords) which form the upper border of the glottis . The glottis includes the vocal cords and anterior commissure and posterior commissure . The sub glottis becomes the trachea at the lower border of the cricoid .( between true v.c . and lower border of the cricoid ) .

8. The framework of the larynx Framework of larynx is formed by cartilages. This cartilages are linked by ligaments and membranes . They move in relation to one another by the action of two groups of muscles i.e intrinsic and extrinsic muscles. . Lined with a the mucosal lining is continuous above with the pharynx and below with that of the trachea .

9. HYOID BONE : U-shaped bone. Provides the upper attachment for many of the extrinsic muscles of the laryn but is not a part of it. Suspends the larynx in the neck .

10. Cartilaginous skeleton of larynx 9 different cartilages present in the larynx . Unpaired cartilages: (thyroid, cricoid , epiglottis) Paired cartilages: ( arytenoid , corniculate ,cuneiform)

11. THYROID CARTILAGE: Thyroid cartilage: Shield like. Largest of the laryngeal cartilages. Has two laminae meet in the midline inferiorly. The angle of fusion between the laminae is about 90 degree in men and 120 degrees in women. The fused anterior borders in men form a projection, which can be easily palpated known as Adams apple The laminae diverge posteriorly . The posterior border of the laminae are prolonged as two slender processes known as the superior and inferior comua .

12. The Oblique Line: The oblique line extends from the superior thryoid tubercle to the inferior thyroid tubercle. The oblique line gives attachment to the following muscles: 1. Thyrohyoid muscle . 2. Sternohyoid muscle . 3. Inferior constrictor muscle .

13. Ligaments attached to the thyroid cartilage: Thyroepiglottic ligament : elastic ligament connecting the epiglottis to the angle of the thyroid cartilage. Vestibular ligament : Also known as the false vocal cord. Vocal ligament: Also known as the true vocal cord is responsible for the generation of voice.Is covered with squamous epithelium unlike the Respiratory tract which is covered by ciliated columnar epithelium, to make it easy for vocal fold to vibrate freely over the vocalis muscle without any restriction

14. CRICOID CARTILAGE The only complete cartilage ring in the whole of the respiratory pathway. Shape like signet ring It lies below the thyroid cartilage. Composed of deep broad quadrilateral lamina and has articular facets for arytenoid cartilage each side upper borders and lateral for inferior cornu of the thyroid cartilage and narrow anterior arch.

15. THE ARYTENOID CARTILAGES Small paired cartilages placed close together on the upper and lateral borders of the cricoid lamina. Pyramidal shaped. Has two projections, forward and lateral projections. The forward projection is also known as vocal proces The vocal folds are attached to the vocal process. The lateral processes are also known as muscular process .

16. CORNICULATE AND CUNEIFORM CARTILAGES The corniculate cartilages are two small conical nodules of elastic fibrocartilage which articulate through a synovial joint with the apices of the arytenoid cartilages. They are situated in the posterior part of the aryepiglottic fold. The cuneiform cartilages are two small elongated flakes of fibroelastic cartilage, one in each margin of the aryepiglottic fold .

17. EPIGLOTTIS Leaf shaped fibroelastic cartilage . Projects upwards behind the tongue and the body of the hyoid bone. . The sides of the epiglottis is attached to the arytenoid cartilages by aryepiglottic folds. The anterior surface of the epiglottis is free and is covered with the same mucous membrane which is of the of pharynx. Forms a single median glossoepiglottic fold and two lateral glossoepiglottic folds. Between these folds lie a depression known as the vallecula . .

18. This long, deeply grooved, floppy epiglottis protects the nasotracheal air passage during sucking.

19. Laryngeal joints

20. Ligaments and membranes of the larynx Extrinsic and Intrinsic ligaments . Extrinsic ligaments : connect the laryngeal cartilages to the hyoid bone above and trachea below. Thyro -hyoid membrane Cricotracheal ligament Hyo-epiglotic ligament

21. Laryngeal fold Vestibular Fold(False vocal cord) The vestibular fold is a fixed fold on each side of the larynx, is formed by mucous membrane covering the vestibular ligament . Vocal Fold (Vocal Cord) The vocal fold is a mobile fold on each side of the larynx and is concerned with voice production. It is formed by mucous membrane covering the vocal ligament .

22. Muscles of the larynx Muscles of the larynx are divided into two sets; Extrinsic muscles Intrinsic muscles

23. EXTRINSIC MUSCLES Sternothyroid muscle-depress the larynx Omohyoid muscles –depress the larynx Sternohyoid muscle- depress the larynx Inferior constrictor muscles-elevate the larynx Thyrohyoid muscles -elevate the larynx Digastric muscles -elevate the larynx Stylohyoid muscles -elevate the larynx Mylohyoid muscles -elevate the larynx

24. Vocal cord regulators Five muscles move the vocal cords; Tensing the Vocal Cords; The Cricothyroid muscle Relaxing the Vocal Cords; The thyroarytenoid muscle (The Vocalis ) Adducting the Vocal Cords; Lateral Cricoarytenoid muscle Abducting the Vocal Cords; Posterior Cricoarytenoid muscle Approximates the Arytenoid cartilages; Transverse Arytenoid muscle

25. Nerves Sensory and motor innervation of the larynx is by two branches of the vagus nerves [CN X]; the superior laryngeal nerves the recurrent laryngeal nerves

26. N.B; The muscles are all supplied by recurrent laryngeal nerve, except The Cricothyroids which are supplied by the anterior branch of the superior laryngeal nerve.

27. Blood supply The major blood supply to the larynx is by the superior and inferior laryngeal arteries

28. Veins superior laryngeal veins drain into superior thyroid veins, which in turn drain into the internal jugular veins inferior laryngeal veins drain into inferior thyroid veins, which drain into the left brachiocephalic veins.

29. lymphatics The lymphatic of the larynx are separated by the vocal folds into ; Lymphatics drain regions above and below the vocal folds; Above the vocal folds follow the superior laryngeal artery and terminate in deep cervical nodes associated with the bifurcation of the common carotid artery below the vocal folds drain into deep nodes associated with the inferior thyroid artery

30. Clinical correlation Laryngomalacia

31. Laryngocoele Dilated sac filled with air (ventricle)

32. Failure of recanalization of larynx 75% at glottic level   Laryngeal webs Glottic Anomalies 

33. Subglottic anomalies Subglottic Stenosis

34. Common Viral Laryngitis Acute Laryngotracheitis (Croup) Secondary Bacterial Laryngitis Acute Supraglottitis Laryngeal Diphtheria Laryngopharyngeal Reflux Traumatic Laryngitis Allergic Laryngitis DISEASES OF THE LARYNX

35. LARYNGEAL CANCER