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Salpingopharyngeal fold

The salpingopharyngeal fold is a mucosal fold in the lateral wall of the nasopharynx, extending from the torus tubarius (the cartilaginous opening of the Eustachian tube) downward into the pharyngeal wall. It overlies the salpingopharyngeus muscle, which assists in elevating the lateral pharyngeal wall and opening the Eustachian tube during swallowing. Understanding its anatomy and imaging appearance is important for radiologists, ENT specialists, and head and neck surgeons, especially when evaluating nasopharyngeal masses, inflammation, or structural anomalies.

Synonyms

  • Salpingopharyngeal arch

  • Lateral nasopharyngeal fold

  • Torus tubarius fold

  • Pharyngeal fold of the Eustachian tube

Function

  • Houses the salpingopharyngeus muscle, which elevates the lateral pharyngeal wall during swallowing

  • Assists in opening the Eustachian tube, allowing middle ear ventilation

  • Contributes to the protection of the nasopharyngeal airway

  • Plays a minor role in swallowing mechanics and resonance

MRI Appearance

T1-weighted images:

  • The fold appears as a thin, intermediate-signal soft tissue structure along the lateral nasopharyngeal wall.

  • Surrounded by air in the nasopharyngeal lumen, which appears as a signal void (black), creating natural contrast.

  • Adjacent muscles (salpingopharyngeus and superior pharyngeal constrictor) show intermediate signal intensity.

  • Pathology such as nasopharyngeal tumors or inflammation may appear hypo- to isointense and enhance after contrast.

T2-weighted images:

  • The fold remains intermediate signal, while surrounding edema, mucosal thickening, or fluid appears hyperintense, aiding in detection of inflammatory or neoplastic changes.

  • Air within the nasopharynx remains signal void, sharply outlining the fold.

STIR (Short Tau Inversion Recovery):

  • Fat suppression highlights edema or tumors.

  • Normal fold remains low to intermediate signal; inflamed or tumorous tissue appears hyperintense, helping to detect subtle pathology.

CT Appearance

  • On CT, the salpingopharyngeal fold is seen as a soft tissue density band along the lateral nasopharyngeal wall.

  • The nasopharyngeal lumen contains air, appearing hypodense (black), providing clear contrast to the fold.

  • Pathology such as nasopharyngeal masses, mucosal thickening, or cysts appears as soft tissue density within or adjacent to the fold.

  • CT is especially useful for assessing bony or cartilaginous involvement and airway patency.

MRI images

Salpingopharyngeal fold mri axial image -img-00000-00000