Core Curriculum Syllabus: Review of Anatomy - The Larynx

The larynx is a valve separating the trachea from the upper aerodigestive tract. It is primarily thought of as an organ of communication--the "voice box"--but it is also an important regulator of respiration, and is necessary for an effective cough or valsalva maneuver, and prevents aspiration during swallowing.

A. Skeleton

  • Hyoid Bone - attachment to epiglottis and strap muscles.
  • Thyroid Cartilage - anterior attachment of vocal folds. Posterior articulation with cricoid cartilage.
  • Cricoid Cartilage - complete ring. Articulates with thyroid and arytenoid cartilages.
  • Arytenoids - two cartilages which glide along the posterior cricoid and attach to posterior ends of vocal folds.

Articulated elements of the larynx

B. Divisions

  • Supraglottis - usually covered with respiratory epithelium containing mucous glands.
    • Epiglottis - leaf-shaped mucosal-covered cartilage, which projects over larynx.
    • Aryepiglottic folds - extend from the lateral epiglottis to the arytenoids.
    • False vocal cords - mucosal folds superior to the true glottis. Separated from true vocal folds by the ventricle.
    • Ventricle - mucosal-lined sac, variable in size which separates the supraglottis from the glottis.
  • Glottis - the true vocal folds attach to the thyroid cartilage at the anterior commissure. The posterior commissure is mobile, as the vocal folds attach to the arytenoids. Motion of the arytenoids effects abduction or adduction of the larynx. The bulk of the vocal fold is made up of muscle covered by mucosa. The free edge is characterized by stratified squamous epithelium. The vocal folds abduct for inspiration and adduct for phonation, cough, and valsalva.
  • Subglottis - below the vocal folds, extending to the inferior border of the cricoid cartilage.

Laryngeal anatomy

 

C. Innervation - branches of the vagus nerve.

  • Superior Laryngeal Nerve - sensation of the glottis and supraglottis. Motor fibers to the cricothyroid muscle, which tenses the vocal folds. This nerve leaves the vagus high in the neck.
  • Recurrent Laryngeal Nerve - sensation of the subglottis, and motor fibers to intrinsic muscles of the larynx. This nerve branches from the vagus in the mediastinum, then turns back up into the neck. On the right, it travels inferior to the subclavian artery and on the left, the aorta.

 

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Bobby R. Alford Department of Otolaryngology-Head and Neck Surgery
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Last modified: Jan. 23, 2006