Larynx USMLE, Limited Edition > Gross Anatomy > Gross Anatomy

Home , Arytenoid cartilage, Cricoid cartilage, Thyroid cartilage, Vocal cords

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.

1 / 2 • 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:

Aryepiglottic ligament, superiorly The vestibular ligament, inferiorly 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.