LARYNGEAL MEMBRANE & MUCOSA

Membranes 
  1.  Extrinsic - Thyrohyoid membrane, cricothyroid & Crico tracheal membrane
  2.  Intrinsic — Quadrangular membrane & Conus elasticus 

 THYROHYOID MEMBRANE
  • Provides an extensive connection between the thyroid cartilage and the hyoid bone bilaterally and anteriorly.
  • Extending from the upper border and the greater horns of the hyoid bone to the superior horns of the thyroid cartilage and its laminae
  • Thickens anteriorly, forming the median thyrohyoid ligament
  • Thickened posterior margin on each side is called the lateral thyrohyoid ligament.
CRICOTRACHEAL MEMBRANE:
  • Connects the most superior tracheal cartilage with the inferior border of the cricoid cartilage
INTINSIC MEMBRANE:
  • Connect the laryngeal cartilages with each other to regulate movement.
  • There are 2 intrinsic membranes :
  1. Conus Elasticus and
  2. Quadrangular membranes.
CONUS ELASTICUS:
  • Conus Elasticus connects the cricoid cartilage with the thyroid and arytenoid cartilages.
  • Composed of dense fibroconnective tissue with abundant elastic fibers.
  • Having 2 parts
  1. Medial cricothyroid ligament —connects the anterior part of the arch of the cricoid cartilage with the inferior border of the thyroid membrane.
  2. Lateral cricothyroid membranes originate on the superior surface of the cricoid arch and rise superiorly and medially to insert on the vocal process of the arytenoid cartilages posteriorly, and to the interior median part of the thyroid cartilage anteriorly.
  • Its free borders form the VOCAL LIGAMENTS
QUADRANGULAR MEMBRANE:
  • Extends from the sides of the epiglottic cartilage anteriorly to the anterolateral surface of the arytenoid cartilage and posteroinferiorly to the corniculate cartilage.
  • With its covering of mucous membrane forms the aryepiglottic fold superiorly and vestibular ligament inferiorly.
  • It forms the medial wall of the piriform recess
  • The paired Quadrangular Membranes connect the epiglottis with the arytenoid and thyroid cartilages.
  • Course posteriorly downward and attach to the corniculate cartilages and the lateral surfaces of the arytenoids.
  • The cuneiform cartilages are embedded within the aryepiglottic folds.
  • The free inferior borders of the quadrangular membranes form the ventricular ligaments, also known as the false vocal folds.
Laryngeal Mucosa:
  • Is mostly of the respiratory type called ciliated columnar epithelium,
  • Certain areas of the larynx covered with stratified squamous epithelium are-
  1. Upper area of the anterior , dorsal epiglottic surfaces,
  2. The ventral half of the aryepiglottic folds, and 
  3. The vocal cords.
  • Mucous membrane of the supraglottic larynx is a downward continuation of the oropharyngeal mucosa.
  • The laryngeal mucosa is supplied by internal laryngeal nerve 
  • Infraglottic region of the larynx is made of normal respiratory mucosa
  • Mucous glands are found at the posterior surface of the epiglottis, aryepiglottic fold, and laryngeal appendices.

Exam Question
  • Extrinsic membrane of larynx are thyrohyoid, cricothyroid & cricotracheal membrane
  • The laryngeal mucosa is supplied by internal laryngeal nerve

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