Epiglottis

1. Overview

The epiglottis is a leaf-shaped elastic cartilage structure located in the larynx that functions as a protective flap. Its primary role is to prevent aspiration by covering the laryngeal inlet during swallowing. This ensures that food and liquids are directed into the esophagus and not the trachea. The epiglottis plays a dual role in the respiratory and digestive systems and is crucial for airway protection during deglutition.

2. Location

The epiglottis is located in the superior part of the larynx, at the level of the C3 vertebra, and lies:

• Posterior to the root of the tongue

• Anterior to the laryngeal inlet and glottis

• Superior to the thyroid cartilage

It projects upward behind the tongue and hyoid bone and is visible during laryngoscopy.

3. Structure

The epiglottis is composed of elastic cartilage, which provides both flexibility and resilience. Key structural features include:

• Shape: Leaf-like or spoon-shaped

• Anterior (lingual) surface: Faces the base of the tongue; covered by stratified squamous epithelium

• Posterior (laryngeal) surface: Faces the laryngeal inlet; covered by pseudostratified columnar ciliated epithelium with mucus-secreting cells

• Stalk (petiolus): The narrow lower end that attaches to the thyroid cartilage via the thyroepiglottic ligament

• Valleculae: Paired spaces between the epiglottis and tongue, separated by the median glossoepiglottic fold—important landmarks in intubation

4. Function

The epiglottis serves several critical functions:

• Swallowing protection: Acts as a lid that closes over the laryngeal inlet during swallowing, directing food and liquids into the esophagus

• Airway patency during breathing: Remains upright and open during respiration, allowing free passage of air into the trachea

• Speech assistance: Plays a minor role in modulating resonance and voice tone

5. Physiological Role(s)

The epiglottis plays a dynamic role in coordinating respiration and digestion:

• Swallowing reflex: Triggered by the contact of food or liquid with the oropharynx, leading to laryngeal elevation and epiglottic closure

• Airway protection reflex: Prevents inhalation of foreign material by reflexively sealing the glottis

• Elastic recoil: After swallowing, it springs back to its resting position to reopen the airway

• Sensory integration: Contains numerous sensory nerve endings that detect irritants and initiate coughing or gag reflexes if necessary

6. Clinical Significance

Epiglottitis

A life-threatening condition characterized by inflammation and swelling of the epiglottis, commonly caused by Haemophilus influenzae type B (Hib). Symptoms include:

• High fever

• Dysphagia and drooling

• Stridor and muffled voice

• Tripod positioning and respiratory distress

It is a pediatric emergency requiring airway management and IV antibiotics. The advent of the Hib vaccine has significantly reduced incidence.

Aspiration Risk

Dysfunction or structural abnormalities of the epiglottis (e.g., due to stroke, surgery, or trauma) can lead to:

• Inadequate closure of the airway

• Risk of aspiration pneumonia

• Chronic coughing during meals

Intubation Landmark

The epiglottis is an important visual guide during laryngoscopy. The vallecula, located anterior to it, is used for optimal blade positioning during intubation.

Congenital Abnormalities

Rarely, infants may have malformed or floppy epiglottis (e.g., in laryngomalacia), which may cause noisy breathing and mild airway obstruction. Most cases resolve without intervention.

Epiglottic Cysts or Tumors

Benign or malignant masses may obstruct the laryngeal inlet and require surgical evaluation and airway management. Symptoms include:

• Hoarseness

• Globus sensation (feeling of a lump in the throat)

• Breathing difficulty if large