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Larynx
Larynx
- The larynx is the start of the lower respiratory tract.
- Superiorly, the larynx is attached to the hyoid bone via connective tissues.
- Three key functions of the larynx:
- It conducts air from the pharynx to the trachea.
- It prevents food and liquid from entering the lower respiratory tract.
- It facilitates the production of speech.
Key anatomical structures:
Three larger, singular cartilages:
- Thyroid cartilage – forms anterior and lateral walls; features the laryngeal prominence.
- Cricoid cartilage – circular, forms base of larynx.
- Epiglottis – "flap" that attaches to the internal surface of the thyroid cartilage, anteriorly, and projects posteriorly and superiorly over the opening of the larynx.
- Upon swallowing, the flap closes off the entryway to the larynx, which prevents foods and liquids from entering the lower respiratory tract.
Three paired sets of smaller cartilages:
- Arytenoid cartilage – articulates with cricoid cartilage posteriorly.
- Corniculate cartilage – sits on arytenoid cartilages.
- Cuneiform cartilage – sits anterior to corniculate cartilages; very small, wedge-shaped.
Membranes and connective tissues:
- Thyrohyoid membrane - connects the thyroid cartilage and hyoid bone.
- Cricothyroid ligament - extends superiorly from the cricoid cartilage to the thyroid and arytenoid cartilages.
- Vocal ligament - thickened superior edge of the cricothyroid ligament comprises the vocal ligament; known as the "true" vocal cord because it facilitates sound production.
- Rima glottides - opening between the vocal cords. During sound production, laryngeal muscles contract to rotate the arytenoid cartilages and alter the opening between the true vocal cords.
- Quadrangular membrane - connects the lateral sides of the epiglottis to the arytenoid cartilages.
- Free edges of the quadrangular membrane thicken to form the:
The vestibular ligament and its mucosal covering are often referred to as the "false vocal cord"; it does not participate in sound production.
Clinical correlations:
Laryngitis is inflammation of the vocal cords, which can stem from infectious or non-infectious causes (such as over-use). It typically results in hoarseness but severe swelling can block the airways.