Anatomy of the Larynx: 3D Model and Function

Laryngeal Structure and Function

• Laryngeal prominence is commonly referred to as the "Adam's apple."
• Cricoid cartilage can be palpated at the level of the sixth cervical vertebra (C6), just inferior to the laryngeal prominence.
• Vocal folds are located at the level of the fourth to sixth cervical vertebrae (C4-C6) in relation to the laryngeal prominence.

Clinical Procedures and Considerations

• Needle cricothyrotomy or coniotomy is performed at the midline of the neck, specifically through the cricothyroid membrane.
• As a fingertip passes over the arch of the cricoid cartilage, it may feel the cartilage’s prominence and rigidity.
• The structure that recedes upon swallowing during neck palpation is the thyroid gland.
• Approximately 10% of people may have a left brachiocephalic artery arising from the arch of the aorta.

Vascular Drainage and Control

• Superior thyroid veins drain into the internal jugular vein.
• The larynx produces sound through the vocal folds, which are controlled by intrinsic laryngeal muscles.
• The main inspiratory sphincter of the larynx is the cricothyroid muscle.

Vocal and Respiratory Protection

• The epiglottis protects the vocal folds and forms an aperture between them during swallowing and breathing.
• The space between the vestibular ligaments is known as the "ventricular space" or "saccule."
• A usual sign of unilateral recurrent laryngeal nerve injury is hoarseness of voice.

Surgical Implications

• Bruising of the recurrent laryngeal nerves during surgery can lead to vocal cord paralysis.
• The right recurrent laryngeal nerve crosses beneath the inferior pole of the thyroid gland.
• A tightly closed larynx prevents the entry of air during activities like holding breath.

Glottic Aperture

• A narrow and wedge-shaped rima glottidis, the opening between the vocal cords, signifies a reduced airway.
• The vestibular folds encompass two thick mucous membrane folds enclosing the vestibular ligaments.
• The isthmus of the thyroid gland lies anterior to the trachea, typically spanning from the second to fourth tracheal cartilages.

Pediatric and Adult Considerations

• In infants and children, the structure covering the inferior part of the trachea is the cricothyroid membrane.
• The surgical cricothyrotomy allows for emergency airway access when intubation is difficult.
• In relation to each other, the first tracheal cartilage is located superiorly to the cricoid cartilage.
• During a tracheostomy in infants and children, there is a risk of encountering the inferior thyroid veins.
• In adults, potential complications during a tracheostomy may include damage to surrounding structures, such as blood vessels and nerves.

Vascular Supply

• The superior thyroid artery primarily supplies the anterosuperior aspect of the thyroid gland.
• The isthmus of the thyroid gland extends to either side of the midline, connecting the left and right lobes.
• The left brachiocephalic vein, jugular venous arch, and pleurae are located posteriorly to the trachea during tracheostomy procedures.

Explore the anatomy of the larynx and its functions with this 3D model. Learn about the laryngeal prominence, thyroid cartilage, vocal folds, and cricoid cartilage, and understand their palpable and visible characteristics.