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Epiglottis

The epiglottis is a leaf-shaped, elastic cartilage structure located in the upper part of the larynx. It plays a crucial role in airway protection during swallowing by covering the glottic opening and preventing aspiration. Understanding the normal appearance of the epiglottis across different imaging modalities is essential for accurate diagnosis of laryngeal pathologies.

ANATOMY & DESCRIPTION

  • The epiglottis is a thin, flexible, cartilaginous structure.

  • It is situated posterior to the tongue and anterior to the laryngeal inlet.

  • Superior surface faces the oropharynx; the inferior stalk attaches to the thyroid cartilage.

  • Composed primarily of elastic cartilage, covered by mucous membrane.

FUNCTION

  • Main function is to act as a protective valve during swallowing.

  • During deglutition, the epiglottis folds posteriorly and inferiorly to cover the laryngeal inlet.

  • Prevents entry of food and liquid into the trachea and lungs.

  • Restores to its upright position after swallowing to allow airflow to the larynx and trachea.

MRI APPEARANCE

T2-Weighted Imaging

  • Epiglottis appears as an intermediate to high signal intensity structure due to its cartilaginous and mucosal components.

  • The surrounding fat and muscle provide good contrast.

  • Edematous or inflamed epiglottis (as in epiglottitis) may show increased T2 signal and thickening.

T1-Weighted Imaging

  • The normal epiglottis demonstrates intermediate to low signal intensity.

  • Surrounding pre-epiglottic fat is of high signal, helping delineate the structure.

  • Pathological changes (e.g., tumor, infection) may cause altered signal intensity or mass effect.

STIR (Short Tau Inversion Recovery)

  • Epiglottis is visualized with suppressed fat signal.

  • Edematous changes (fluid, inflammation) stand out as high signal intensity areas.

  • Useful for detecting subtle edema, infection, or neoplastic infiltration.

CT APPEARANCE

  • Epiglottis appears as a soft tissue density structure, slightly higher density than the surrounding fat.

  • Normally measures less than 3 mm in thickness at the free edge (in adults).

  • On contrast-enhanced CT, mucosal enhancement may be seen.

MRI images

Epiglottis mri axial image