Anatomy of Laryngeal Structures Quiz

Larynx Anatomy

• The larynx is a hollow structure with a cartilaginous framework, responsible for voice production and acting as a sphincter to close the lower respiratory tract.
• Located below the tongue and hyoid bone, it opens above into the laryngeal part of the pharynx and continues below into the trachea.

Cartilages of the Larynx

• The larynx is composed of three large unpaired cartilages (thyroid, cricoid, and epiglottis) and three pairs of smaller cartilages (arytenoid, corniculate, and cuneiform).
• Thyroid cartilage:
  • Largest cartilage of the larynx
  • Consists of two laminae of hyaline cartilage meeting in the midline at the prominent V angle (Adam's apple)
  • Angle between the two laminae is more acute in men (90°) than in women (120°)
  • Posterior border extends upward into a superior cornu and downward into an inferior cornu
  • Outer surface has an oblique line for muscle attachment
• Cricoid cartilage:
  • Shaped like a signet ring
  • Lies below the thyroid cartilage and completely encircles the airway
  • Lateral surface has a facet for articulation with the inferior cornu of the thyroid cartilage
  • Posteriorly, the lamina has a facet for articulation with the arytenoid cartilage on each side
• Epiglottis:
  • Leaf-shaped lamina of elastic cartilage
  • Lies behind the root of the tongue
  • Stalk is attached to the back of the thyroid cartilage via the thyro-epiglottic ligament
  • Sides are attached to the arytenoid cartilages by the aryepiglottic folds of mucous membrane
  • Upper edge is free

Arytenoid Cartilages

• Two pyramid-shaped cartilages sitting on the cricoid cartilage
• Apex articulates with the corniculate cartilage
• Base articulates with the superior border of the cricoid cartilage
• Vocal process and muscular process are present

Membranes and Ligaments of the Larynx

• Extrinsic membrane and ligament:
  • Thyrohyoid membrane connects the upper margin of the thyroid cartilage to the hyoid bone
  • Thyroepiglottic ligament connects the inferior end of the epiglottic cartilage to the posterior median aspect of the thyroid lamina
  • Hyoepiglottic ligament connects the anterior surface of the epiglottis to the body of the hyoid bone
  • Cricotracheal ligament connects the cricoid cartilage to the first ring of the trachea
• Intrinsic membrane and ligaments:
  • Fibro-elastic membrane of the larynx links together the laryngeal cartilages and completes the architectural framework of the laryngeal cavity
  • Upper quadrangular membrane extends between the epiglottis and the arytenoid cartilages
  • Lower cricothyroid ligament (cricovocal membrane and cricothyroid membrane) attaches to the upper border of the cricoid cartilage and forms the vocal ligament

Laryngeal Folds

• Vestibular Fold (false vocal cord):
  • Fixed fold on each side of the larynx
  • Formed by mucous membrane covering the vestibular ligament
  • Vascular and pink in color
• Vocal Fold (true vocal cord):
  • Mobile fold on each side of the larynx
  • Concerned with voice production
  • Formed by mucous membrane covering the vocal ligament
  • Vascular and white in color
  • Gap between the vocal folds is called the rima glottidis

Inlet of the Larynx

• Opening from the pharynx into the larynx
• Formed in front by the epiglottis, laterally by the aryepiglottic fold of mucous membrane, and posteriorly by the arytenoid cartilages with the corniculate cartilages

Muscles of the Larynx

• Extrinsic muscles:
  • Move the larynx up and down and forward and backward during swallowing
  • Attached to the hyoid bone, suprahoid muscles elevate the larynx, and infrahyoid muscles depress the larynx
• Intrinsic muscles:
  • Modify the laryngeal inlet
  • Five muscles move the vocal folds (cords)

Nerve Supply of the Larynx

• Sensory nerves:
  • Above the vocal cords: Superior laryngeal branch of the vagus
  • Below the vocal cords: Recurrent laryngeal nerve
• Motor nerves:
  • All intrinsic muscles of the larynx except the cricothyroid muscle are supplied by the recurrent laryngeal nerve
  • Cricothyroid muscle is supplied by the external laryngeal branch of the vagus

Blood Supply of the Larynx

• Upper half of the larynx: Superior laryngeal branch of the superior thyroid artery
• Lower half of the larynx: Inferior laryngeal branch of the inferior thyroid artery