QS Study

Interior of the Larynx

The larynx is the organ for phonation. It is an organ located in the anterior neck. It is located within the anterior aspect of the neck, anterior to the inferior portion of the pharynx and superior to the trachea. It goes from the root of the tongue to the trachea and is located in front of the 3rd, 4th, 5th, and 6th cervical vertebrae. It is a component of the respiratory tract.

Features: The cavity of the larynx extends from the inlet of the larynx to the lower border of cricoid cartilage backward and upwards and opens into the laryngopharynx. Their primary function is to protect the airway and make sure nothing unwanted goes down the trachea in the lungs.

The inlet is bounded:

Anteriorly: by the epiglottis.

Posteriorly: By the interarytenoid fold of mucous membrane on each side by the aryepiglottic fold. Within the cavity of the larynx, there are two mucous membrane folds on each side the upper vestibular fold and the lower vocal fold. The space between the vestibular folds is rima vestibuli and the space between the vocal folds is rima glottidis. The rima glottidis is the narrowest part of the larynx.

Parts: The vestibular and vocal folds divide the cavity of the larynx into three parts.

  1. The part above the vestibular fold is called the vestibule of the larynx.
  2. The part between the vestibular and vocal fold is called the ventricle or sinus of the larynx.
  3. The part below the vocal fold is called the infraglottic part.

Lining epithelium: The anterior surface and upper half of the posterior surface of the epiglottis; aryepiglottic folds and vocal fold are covered by stratified squamous epithelium. The rest of the area is covered by ciliated columnar epithelium.

Interior of the Larynx 1

Fig: Interior of the Larynx

Blood supply

Up to vocal cords: By the superior laryngeal artery, the branch of the superior thyroid artery.

Below vocal cords: by inferior laryngeal artery, branch of superior thyroid artery.

Nerve supply

Motor: All the intrinsic muscles are supplied by recurrent laryngeal nerve except for cricothyroid which is supplied by the external laryngeal nerve.

Sensory:

  • Up to vocal folds: By internal laryngeal nerve.
  • Below vocal folds: By recurrent laryngeal nerve.
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