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4 the larynx(anatomy)


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4 the larynx(anatomy)

  1. 1. The Larynx (Anatomy and physiology) The First Affiliated Hospital of Sun –Yatsen University Aiyun jiang
  2. 2. The Larynx <ul><li>the meeting place of voice, swallow and airway. </li></ul><ul><li>The larynx is an arrangement of several cartilages held together by ligaments and muscles. It is connected above with the hypopharynx and below with the trachea. </li></ul><ul><li>Out side the cartilagous framework are the strap muscles of the neck. </li></ul><ul><li>Behind the larynx are the third,fourth, fifth and sixth cervical vertebrae. </li></ul>
  3. 4. The Larynx(Anatomy) <ul><li>CONTENTS </li></ul><ul><li>Framework </li></ul><ul><li>Cartilages (*cricoid) </li></ul><ul><li>(Joints) </li></ul><ul><li>Muscles(*abductor) </li></ul><ul><li>Membranes and ligaments </li></ul><ul><li>* Laryngeal cavity </li></ul><ul><li>Nerve </li></ul><ul><li>Blood supply </li></ul><ul><li>Lymphatic drainage </li></ul>
  4. 5. cartilages <ul><li>There are four cartilages: </li></ul><ul><li>thyroid, cricoid, </li></ul><ul><li>arytenoid, epiglottic. </li></ul><ul><li>(1)Thyroid:the largest and </li></ul><ul><li>most prominent .The </li></ul><ul><li>thyroid cartilage shields </li></ul><ul><li>the intrinsic part of the </li></ul><ul><li>larynx anteriorly and laterally. </li></ul><ul><li>It consists of two flat lamina which fused in the midline anteriorlly and open posteriorly. Extending upward from each lamina is the superior cornu , and extending downward is the inferior cornu. At its top, is the thyroid notch </li></ul>
  5. 6. . <ul><li>(2)Cricoid:The cricoid </li></ul><ul><li>looks like a signet </li></ul><ul><li>ring,with a broad , </li></ul><ul><li>flat, posterior lamina. </li></ul><ul><li>* It is the only complete </li></ul><ul><li>ring of cartilage in the </li></ul><ul><li>larynx. And it differs </li></ul><ul><li>from all other tracheal rings that it forms a complete circle. So it is the only rigid area in the respiratory tree. It is very important in maintaining the normal lumen of respiratory tract </li></ul>
  6. 7. . <ul><li>(3)Arytenoid. are a </li></ul><ul><li>pair of small </li></ul><ul><li>pyramid-shape </li></ul><ul><li>cartilages . Perch </li></ul><ul><li>on top of the </li></ul><ul><li>lamina of cricoid </li></ul><ul><li>Each Arytenoids cartilage has two processes: a vocal process, to which the posterior end of vocal ligaments is attached, and a muscular process, to which the intrinsic laryngeal muscle is attached. </li></ul>
  7. 8. . <ul><li>(4)Epiglottic cartilage:a pear-shaped,curved plate of cartilages covered by mucosa on both surfaces. </li></ul><ul><li>The superior half is above the level of hyoid bone and projects freely into the oropharynx. </li></ul>
  8. 9. joints <ul><li>There are just two pair of joints in the larynx,the cricoarytenoid(CA) and cricothyroid(CT),all the internal adjustments of the vocal cords are medeated through them. </li></ul><ul><li>CA: Enables the vocal cords to drawn away from the midline(abduction) or brought to midline(adduction). </li></ul><ul><li>CT: It is important in pitch control and provides a mechanism for regulating the </li></ul><ul><li>lengthening of the vocal folds. </li></ul><ul><li>When these two cartilages are </li></ul><ul><li>pulled towards each other, the </li></ul><ul><li>vocal folds are lengthened, when </li></ul><ul><li>towards apart,the vocal folds are </li></ul><ul><li>shortened. </li></ul>
  9. 10. .
  10. 11. Muscles(1) <ul><li>(1)Abductor Muscles:posterior cricoarytenoid muscle(PCA). </li></ul><ul><li>The major muscles responsible for the arytenoid rocking </li></ul><ul><li>and gliding apart, and for the abduction of the vocal </li></ul><ul><li>folds. </li></ul><ul><li>(2)Adductor muscles: </li></ul><ul><li>1) interarytenoid muscles(IA): Their action is to pull the </li></ul><ul><li>upper tips of the arytenoids together. </li></ul><ul><li>2)lateral cricoarytenoid muscles(LCA): adduct the </li></ul><ul><li>arytenoids and are also able to squeeze the anterior tips of </li></ul><ul><li>the vocalprocesses tightly in a condition of medial </li></ul><ul><li>compression. </li></ul>
  11. 12. Muscles(2) <ul><li>(3)Tensor Muscles: Cricothyroid muscles(CT). Originate </li></ul><ul><li>from the front of the cricoid cartilages and insert into </li></ul><ul><li>the thyroid cartilage. </li></ul><ul><li>*J ust remember PCA is responsible for abduction of VC , IA and LCA are responsible for adduction of VC,CT is responsible for tense of VC </li></ul>
  12. 13. Membranes and Ligaments <ul><li>(1)Conus elasticus:Its free edge thickens to form the vocal ligaments (which lie between the arytenoid and thyroid cartilages ) and False vocal folds ( which is above the true vocal folds) </li></ul><ul><li>(2)Thyrohyoid membrane:between the hyoid bone and the thyroid cartilage. </li></ul><ul><li>(3)Cricothyroid membrane:between the cricoid and thyroid cartilages.At this point the lumen of the airway is closest to the skin of the neck and therefore, most accessible in an emergency. </li></ul>
  13. 14. .
  14. 15. Laryngeal cavity <ul><li>(1)supraglottis: the part of </li></ul><ul><li>the larynx above the level </li></ul><ul><li>of the vocal cords. </li></ul><ul><li>It consists of the epiglottis, </li></ul><ul><li>the aryepiglottic folds, </li></ul><ul><li>the ventricular band and </li></ul><ul><li>the laryngeal ventricle. </li></ul><ul><li>(2)glottis:the space between the vocal cords. </li></ul><ul><li>(3)subglottis: the part of the larynx below the level </li></ul><ul><li>of the vocal cords. </li></ul>
  15. 16. .
  16. 17. Blood supply <ul><li>The superior thyroid artery through its branch, superior laryngeal artery </li></ul><ul><li>The inferior thyroid artery through its branch, inferior laryngeal artery </li></ul><ul><li>Provide most of the blood supply to the larynx </li></ul>
  17. 18. .
  18. 19. Nerve supply <ul><li>the entire laryngeal nerve supply </li></ul><ul><li>is from the vagus </li></ul><ul><li>(1)recurrent laryngeal nerves </li></ul><ul><li>provide the motor supply </li></ul><ul><li>to the intrinsic muscles of </li></ul><ul><li>the larynx and the sensory </li></ul><ul><li>innervation to the subglottis. </li></ul><ul><li>(2)Superior laryngeal </li></ul><ul><li>nerve are the motor </li></ul><ul><li>nerves of the cricothyroid </li></ul><ul><li>muscles and provide the sensory supply to the supraglottis and glottis. </li></ul><ul><li>. </li></ul>
  19. 20. Lymphati drainage <ul><li>(1)the supraglottis:is richly supplied with lymphatic vessels which drain into the ipsilateral midjugular lymph nodes. </li></ul><ul><li>(2)the vocal cords have few lymphatic spaces and poor lymphatic drainage. </li></ul><ul><li>(3)the subglottis is richly supplied with lymphatic vessels which empty into the paratracheal nodes and the Delphian node. </li></ul><ul><li>so carcinoma metastasis of the supraglottis may occur in early stage of the tumor </li></ul><ul><li>carcinoma metastasis of the glottis is not common if the tumor doesn’t involve the supraglottis and subglottis </li></ul>
  20. 21. Chracters of larynx in children <ul><li>1 、 location: high 2 、 cartilages:soft 3 、 pultaceous connect tissue , richly supplied </li></ul><ul><li>with lymphatic vessels </li></ul><ul><li>4 、 lumen(space): narrow 5 、 curved epiglottis 6 、 short VC, high pitch </li></ul>
  21. 22. Physiology of the Larynx <ul><li>1 Protection:To protect the lower respiratory passages(cough reflex, sphincteric action—three levels) </li></ul><ul><li>2 Respiration: To conduct air to and from the lungs </li></ul><ul><li>3 phonation: To function as a vocal organ </li></ul><ul><li>4 To fix the chest in heavy physical effort </li></ul>