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Thyrohyoid membrane

The thyrohyoid membrane is a broad, fibroelastic structure that connects the thyroid cartilage of the larynx to the hyoid bone. It forms the superior boundary of the larynx and provides a passage for neurovascular structures, including the internal branch of the superior laryngeal nerve and the superior laryngeal vessels. Knowledge of its anatomy, function, and imaging characteristics is essential for radiologists, ENT surgeons, and head and neck specialists, especially in the assessment of airway pathology, trauma, or surgical planning.

Synonyms

  • Thyrohyoid ligament

  • Superior laryngeal membrane

  • Ligamentum thyrohyoideum

Function

  • Connects the thyroid cartilage to the hyoid bone, maintaining laryngeal position.

  • Supports the laryngeal inlet and contributes to airway stability.

  • Provides a protective passage for the internal branch of the superior laryngeal nerve and vessels.

  • Facilitates movement of the larynx during swallowing and phonation.

MRI Appearance
T1-weighted images:

  • The thyrohyoid membrane appears as a thin, low signal intensity band between the hyoid bone and thyroid cartilage.

  • Surrounding fat is hyperintense, providing contrast to delineate the membrane.

  • Pathological conditions, such as edema or infection, may slightly increase signal intensity.

T2-weighted images:

  • The membrane is hypointense to intermediate signal, with surrounding soft tissue or edema appearing hyperintense.

  • Useful for detecting inflammatory changes, hematoma, or masses adjacent to the membrane.

STIR (Short Tau Inversion Recovery):

  • Fat suppression enhances visibility of edema or pathological changes.

  • Normal thyrohyoid membrane remains low signal, while inflammatory or neoplastic lesions appear hyperintense.

CT Appearance

  • On CT, the thyrohyoid membrane is a soft tissue density structure connecting the hyoid bone to the thyroid cartilage.

  • The air-filled laryngeal vestibule lies just inferior, appearing hypodense (black), providing natural contrast.

  • Cartilages (thyroid, hyoid) are intermediate density, with ossified portions appearing hyperdense.

  • CT is particularly useful for evaluating trauma, calcifications, or masses involving the membrane and surrounding structures.

MRI images

Thyrohyoid Membrane mri axial image -img-00000-00000