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Laryngopharynx

The laryngopharynx, also known as the hypopharynx, is the lower portion of the pharynx extending from the hyoid bone down to the cricoid cartilage, where it continues as the esophagus. It lies posterior to the larynx and superior to the esophagus, serving as a conduit for both air and food. Understanding its anatomy, function, and imaging characteristics is critical for radiologists, ENT specialists, and surgeons, particularly when evaluating tumors, inflammation, trauma, or congenital anomalies.

Synonyms

  • Hypopharynx

  • Inferior pharynx

  • Pharyngeal inlet to esophagus

  • Lower pharyngeal segment

Function

  • Serves as a passageway for air to the larynx and trachea, and food to the esophagus

  • Participates in swallowing, directing bolus posteriorly while protecting the airway

  • Supports resonance during phonation as part of the pharyngeal cavity

  • Protects the airway via the epiglottis and pharyngeal constrictor muscles

MRI Appearance

T1-weighted images:

  • The laryngopharynx lumen is filled with air, which appears as a signal void (black).

  • The posterior pharyngeal wall, mucosa, and surrounding muscles appear intermediate signal intensity, slightly darker than adjacent fat.

  • Parapharyngeal fat is hyperintense, providing natural contrast.

  • Pathological lesions, such as tumors or edema, appear hypo- to isointense relative to muscle and may enhance with contrast.

T2-weighted images:

  • Air remains signal void (black), clearly delineating the lumen.

  • Mucosa, soft tissues, and edema appear intermediate to hyperintense, helping detect inflammatory or neoplastic changes.

  • Surrounding fat remains hyperintense, improving visualization of the hypopharyngeal walls.

STIR (Short Tau Inversion Recovery):

  • Fat suppression removes signal from parapharyngeal fat, highlighting pathological changes.

  • Normal walls appear low-to-intermediate signal, while inflammation, edema, or tumors appear bright hyperintense, facilitating early detection.

CT Appearance

  • On non-contrast CT, the laryngopharynx is air-filled, appearing as hypodense (black).

  • The walls of the hypopharynx, including the posterior pharyngeal wall and piriform sinuses, appear soft tissue density.

  • Surrounding cartilages (cricoid, thyroid) appear intermediate density, with calcifications or ossifications being hyperdense.

  • Pathological findings, such as tumors, mucosal thickening, or abscesses, are visualized as soft tissue density within the normally air-filled lumen.

  • CT is particularly useful for evaluating airway obstruction, tumor invasion, trauma, or bony/cartilaginous abnormalities.

MRI images

Laryngopharynx mri-img-00000-00000