E.N.T 5th year, 1st lecture (Dr. Hiwa)


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The lecture has been given on Feb. 7th, 2011 by Dr. Hiwa.

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E.N.T 5th year, 1st lecture (Dr. Hiwa)

  1. 1. Prepared by Dr.Hiwa As’ad Anatomy and Physiology of the Larynx
  2. 2. Anatomy of the larynx <ul><li>Larynx is situated in the midline of the neck. </li></ul><ul><li>From 3 rd to 6 th cervical vertebrae. </li></ul><ul><li>Consists of a framework of cartilages, connected by ligaments and membranes,lined by a mucous membrane and moved by muscles. </li></ul>
  3. 3. Laryngeal cartilages <ul><li>Unpaired </li></ul><ul><li>Thyroid </li></ul><ul><li>Cricoid </li></ul><ul><li>epiglottis </li></ul><ul><li>Paired </li></ul><ul><li>Arytenoid </li></ul><ul><li>Corniculate </li></ul><ul><li>Cuneiform </li></ul>
  4. 4. Thyroid cartilage <ul><li>The largest, each </li></ul><ul><li>half consists of </li></ul><ul><li>Ala (lamina) </li></ul><ul><li>A square plate; </li></ul><ul><li>Begin to ossify at 25; </li></ul><ul><li>May be completely converted to bone at 65. </li></ul>
  5. 5. Thyroid cartilage <ul><li>The 2 ala meet in the midline; </li></ul><ul><li>Forming an angle of </li></ul><ul><li>- 90 in men; </li></ul><ul><li>-120 in women. </li></ul><ul><li>Forming V shape notch called a thyroid notch or Adam ’ s apple. </li></ul>
  6. 6. Thyroid cartilage <ul><li>An oblique line is running downward and foreward on the surface of each lamina, </li></ul><ul><li>It is the site of muscular attachment. </li></ul>
  7. 7. Cricoid cartilage <ul><li>Resembles a signet ring, narrow in front and broad behind. </li></ul><ul><li>Ossification begins at 30 and may be complete by 65. </li></ul><ul><li>Consists of lamina and arch. </li></ul>
  8. 8. Cartilage of epiglottis <ul><li>Rises up behind the tongue. </li></ul><ul><li>It is a thin leaf-like sheet of elastic fibrocartilage. </li></ul><ul><li>The stem is long and thin and attached to the posterior surface of thyroid alae at their junction. </li></ul><ul><li>The free upper border is broad and rounded. </li></ul>
  9. 9. Cartilage of epiglottis <ul><li>Anterior surface : </li></ul><ul><li>Free in upper part. </li></ul><ul><li>In its lower part is separated from hyoid bone and thyrohyoid membrane by fatty tissue </li></ul><ul><li>(pre-epiglottic space) </li></ul>
  10. 10. Cartilage of epiglottis <ul><li>Posterior surface : </li></ul><ul><li>Is indented by several small pits, in which mucous glands are embeded. </li></ul>The tubercle of epiglottis projects backwards in its lower part.
  11. 11. Arytenoid cartilages <ul><li>Pyramidal in shape; </li></ul><ul><li>Posterior surface is triangular and concave, it extend laterally into a muscular process. </li></ul>
  12. 12. Arytenoid cartilages <ul><li>Anterolateral surf. is convex, it extends foreward into a vocal process. </li></ul>
  13. 13. Corniculate cartilages (The cartilages of Santorini) <ul><li>They articulate with the apices of the arytenoid cartilages and prolong them backwards and medially. </li></ul><ul><li>They give attachments to the upper fibers of the oesophagus. </li></ul>
  14. 15. Cuneiform cartilages (The cartilages of Wrisberg) <ul><li>Are small bars of yellow elastic cartilage. </li></ul><ul><li>There is one in each ary-epiglottic fold, where it acts as a passive prop. </li></ul><ul><li>They do not articulate with any other cartilage. </li></ul>
  15. 17. Laryngeal joints <ul><li>Crico-thyroid joint. </li></ul><ul><li>Crico-arytenoid joint . </li></ul>
  16. 18. Laryngeal ligaments and membranes <ul><li>Intrinsic : </li></ul><ul><li>Uniting the cartilages of the larynx to one another. </li></ul><ul><li>Extrinsic : </li></ul><ul><li>Uniting the cartilages of the larynx to the skeletal structures outside the larynx. </li></ul>
  17. 19. Intrinsic laryngeal ligaments and membranes <ul><li>The elastic membrane of the larynx. </li></ul><ul><li>Thyroepiglottic ligament. </li></ul>
  18. 20. The elastic membrane of the larynx. <ul><li>It is the fibrous framework of the larynx. </li></ul><ul><li>It lies beneath the laryngeal mucosa. </li></ul><ul><li>It is divided into upper & lower part by the ventricle of the larynx </li></ul>
  19. 21. The elastic membrane of the larynx. <ul><li>- Contribute to the support of the aryepiglottic and ventricular folds. </li></ul><ul><li>-The ventricular ligament is a thickening of the free border. </li></ul>The upper part(Quadrangular mem.)
  20. 22. The elastic membrane of the larynx. <ul><li>The lower part (conus elasticus or cricovocal mem.) </li></ul><ul><li>Inferiorly </li></ul><ul><li>it is attached to the superior border of the cricoid cartilage. </li></ul>
  21. 23. Conus elasticus <ul><li>Superiorly it is attached: </li></ul><ul><li>Infront to the deep surface of the angle of the thyroid cartilage. The median cricothyroid ligament is formed by the thickened anterior part of the conus. </li></ul>
  22. 24. Conus elasticus <ul><li>Behind attached to the vocal process of the arytenoid cartilage. </li></ul>
  23. 25. Conus elasticus <ul><li>The vocal ligament is the free upper edge of the conus between these points of attachments. </li></ul>
  24. 26. Intrinsic laryngeal ligaments and membranes <ul><li>2. Thyroepiglottic lig . </li></ul><ul><li>. </li></ul>Attaches the epiglottis to the thyroid cartilage
  25. 27. Extrinsic laryngeal ligaments and membranes <ul><li>Thyrohoid membrane </li></ul><ul><li>It is a broad sheet of fibro-elastic tissue attaches the upper border of thyroid cartilage and hyoid bone. </li></ul>
  26. 28. Thyrohoid membrane <ul><li>The subhyoid bursa separates the membrane from the posterior surface of the body of hyoid bone. </li></ul><ul><li>Upward movement of the larynx during deglutition is facilitated by the bursa. </li></ul><ul><li>The membrane is pierced on each side by: </li></ul><ul><li>- superior laryngeal vessels. </li></ul><ul><li>- internal branch of superior laryngeal nerve. </li></ul>
  27. 29. Extrinsic laryngeal ligaments and membranes <ul><li>Median thyrohyoid ligament. </li></ul><ul><li>Lateral thyrohyoid ligament. </li></ul><ul><li>Cricotracheal membrane. </li></ul><ul><li>Hyo-epiglottic ligament. </li></ul>
  28. 30. Intrinsic laryngeal muscles <ul><li>Abductors of the vocal cords. </li></ul><ul><li>Adductors of the vocal cords. </li></ul><ul><li>Tensors of the vocal cords. </li></ul><ul><li>Openers of laryngeal inlets. </li></ul>
  29. 31. Abductors of the vocal cords Posterior crico-arytenoid muscle
  30. 33. Posterior crico-arytenoid muscle
  31. 34. Adductors of the vocal cords <ul><li>Are 3 on each side: </li></ul><ul><li>Lateral crico-arytenoid muscle. </li></ul><ul><li>Transverse portion of interarytenoid muscle. </li></ul><ul><li>External portion of thyro-arytenoid muscle. </li></ul>
  32. 35. Lateral crico-arytenoid muscle
  33. 37. Lateral crico-arytenoid muscle
  34. 38. Transverse portion of interarytenoid muscle
  35. 40. Action of transverse portion of interarytenoid muscle
  36. 41. External portion of thyro-arytenoid muscle
  37. 43. Thyro-arytenoid muscle
  38. 44. Tensors of the vocal cords <ul><li>Cricothyroid muscle ( external tensor). </li></ul><ul><li>Internal portion of thyro-arytenoid (vocalis muscle). </li></ul>
  39. 45. Cricothyroid muscle (external tensor)
  40. 46. Action of cricothyroid muscle
  41. 47. Internal portion of thyro-arytenoid (vocalis muscle)
  42. 49. Openers of the laryngeal inlet <ul><li>Thyro-epiglottic muscle </li></ul>
  43. 50. Closers of the laryngeal inlet <ul><li>Oblique portion of interarytenoid muscle. </li></ul>
  44. 52. Closers of the laryngeal inlet <ul><li>Aryepiglottic muscle </li></ul>
  45. 53. Extrinsic muscles of the larynx <ul><li>Between the larynx and neighbouring structures; are 2 main groups: </li></ul><ul><li>Strap muscles. (sternothyroid & thyrohyoid). </li></ul><ul><li>Pharyngeal muscles. </li></ul>
  46. 54. Strap muscles
  47. 55. Cavity of the larynx <ul><li>2 folds </li></ul><ul><li>False vocal cord. </li></ul><ul><li>True vocal cord. </li></ul><ul><li>3 parts </li></ul><ul><li>Vestibule. </li></ul><ul><li>Ventricle. </li></ul><ul><li>Subglottic space </li></ul><ul><li>Extends from the inlet of the larynx to the lower border of the cricoid cartilage, it is divided into 3 parts by 2 folds of mucous membrane: </li></ul>
  48. 56. Vestibule. Ventricle. Subglottic space
  49. 57. False vocal cord <ul><li>These are the ventricular bands which are formed by the mucous membrane covering the ventricular ligament and the upper part of the external portion of the thyroarytenoid muscle. </li></ul>
  50. 58. True vocal cords <ul><li>Project further into than the false cords, and lie at a lower level. </li></ul><ul><li>The covering epithelium is closely bound down to the underlying vocal ligament. </li></ul><ul><li>The blood supply is poor, hence the pearly white appearance of the vocal cords. </li></ul>
  51. 59. Vestibule <ul><li>Bounderies: </li></ul><ul><li>Posterior surface of epiglottis in front. </li></ul><ul><li>Interval between the arytenoid cartilages behind. </li></ul><ul><li>Inner surface of the aryepiglottic folds and upper surfaces of the false cords on each side. </li></ul><ul><li>Lies between the laryngeal inlet and the edges of the false cords. </li></ul>
  52. 60. Ventricle of the larynx <ul><li>A recess between the true and false cords. </li></ul><ul><li>It is lines by mucous membrane which is covered externally by the thyroarytenoid muscle. </li></ul><ul><li>Compsed of 2 parts </li></ul><ul><li>Saccule. </li></ul><ul><li>Rimaglottidis. </li></ul>
  53. 61. Saccule <ul><li>The saccule is a conical pouch which ascends from the anterior part of the ventricle </li></ul><ul><li>It lies between the inner surface of thyroid cartilage and the false cords. </li></ul><ul><li>Numerous mucous glands open onto the surface of its lining mucosa. </li></ul>
  54. 62. Vestibule. Ventricle. Subglottic space
  55. 63. Large laryngeal saccule
  56. 64. Rima glottidis <ul><li>The glottis (rima glottidis) is the interval between: </li></ul><ul><li>The true vocal cord in its anterior 3/5. </li></ul><ul><li>The vocal processes of the arytenoid cartilages in its posterior 2/5. </li></ul><ul><li>Its average length: </li></ul><ul><li>In the adult male is about 2.5 cm. </li></ul><ul><li>In the adult female is about 1.6 cm. </li></ul>
  57. 66. Subglottic space <ul><li>Lies between the true vocal cord and the lower border of the cricoid cartilage. </li></ul>
  58. 67. Blood supply of the larynx <ul><li>Laryngeal branches of the superior thyroid artery. </li></ul><ul><li>Laryngeal branches of the inferior thyroid artery. </li></ul><ul><li>Cricothryoid branches of superior thyroid artery (cross the midline at the upper part of the cricothyroid membrane). </li></ul>
  59. 68. Blood supply of the larynx Inferior thyroid artery superior thyroid artery
  60. 69. Nerve supply of the larynx supplied by branches of vagus <ul><li>Superior laryngeal nerve, has 2 branches: </li></ul><ul><li>Internal. </li></ul><ul><li>External. </li></ul><ul><li>Recurrent (Inferior) laryngeal nerve : </li></ul><ul><li>Anterolateral (motor) </li></ul><ul><li>Posteromedial(sensory) </li></ul>
  61. 70. Superior laryngeal nerve External branch <ul><li>Travel down on the inferior constrictor muscle of the pharynx. </li></ul><ul><li>Supplies the cricothyroid muscle and part of the anterior subglottis. </li></ul>
  62. 71. Suprior laryngeal nerve Internal branch <ul><li>-Entirely sensoy. </li></ul><ul><li>- Pierces the thyrohyoid membrane with the superior laryngeal artery and vein. </li></ul><ul><li>-Supplies the cavity of the larynx as far down as the level of the vocal cords. </li></ul>
  63. 72. Recurrent (Inferior) laryngeal nerve <ul><li>longer coarse on the left. </li></ul><ul><li>In the left it turns round the arch of the aorta. </li></ul><ul><li>On the right it turns round the subclavian artery. </li></ul><ul><li>In the neck it lies between the trachea and the oesophagus </li></ul>
  64. 73. Recurrent (Inferior) laryngeal nerve <ul><li>Its terminal part passes upward, under cover of the ala of the thyroid cartilage immediately behind the inferior cricothyroid joint, it then divided into: </li></ul><ul><li>Anterolateral (motor) branch which supplies all the intrisic muscles of the larynx except cricothyroid muscle. </li></ul><ul><li>Postromedial (sensory) branch which supplies the cavity of the larynx below the level of the vocal cords. </li></ul>
  65. 74. Lymphatic drainage of the larynx <ul><li>Vocal cord has no lymphatic vessels. </li></ul><ul><li>The edges of the vocal cord divide the lymphatic of the larynx into 2 parts: </li></ul><ul><li>Supraglottic drain into: </li></ul><ul><li>2. Subglottic drain into: </li></ul><ul><li>Pre-epiglottic nodes. </li></ul><ul><li>Upper deep cervical nodes. </li></ul><ul><li>Prelaryngeal and pretracheal nodes. </li></ul><ul><li>Lower deep cervical. </li></ul>
  66. 75. Lymphatic drainage of the larynx
  67. 76. Physiology of the larynx: <ul><ul><ul><ul><li>1. Respiration. </li></ul></ul></ul></ul><ul><ul><ul><ul><li>2. Protection of the lower air passages. </li></ul></ul></ul></ul><ul><ul><ul><ul><li>3. Phonation. </li></ul></ul></ul></ul><ul><ul><ul><ul><li>4. Fixation of the chest. </li></ul></ul></ul></ul><ul><ul><ul><ul><li>5. Sphencteric action. </li></ul></ul></ul></ul>
  68. 77. Thank you