Topics

Topic

design image
Thyrohyoid muscle

The thyrohyoid muscle is a short, slender strap muscle located in the anterior neck. Part of the infrahyoid (strap) muscle group, it extends from the thyroid cartilage to the hyoid bone, playing a key role in swallowing and the movement of the larynx. Its anatomical position and unique innervation make it clinically significant for various head and neck procedures as well as radiological imaging.

Anatomy of the Thyrohyoid Muscle

  • Origin:

    • Oblique line of the thyroid cartilage of the larynx.

  • Insertion:

    • Inferior border of the body and greater horn (cornu) of the hyoid bone.

  • Function:

    • Elevates the larynx during swallowing.

    • Depresses the hyoid bone.

    • Assists in phonation by stabilizing laryngeal structures.

  • Nerve Supply:

    • Innervated by the first cervical nerve (C1), which travels with the hypoglossal nerve (cranial nerve XII) before separating to supply the thyrohyoid.

  • Artery Supply:

    • Superior thyroid artery (branch of the external carotid artery).

    • Occasionally, small branches from the lingual artery.

  • Vein Supply:

    • Superior thyroid vein, which drains into the internal jugular vein.

Imaging Appearance

  • MRI Appearance:

    • T1-weighted images:

      • The thyrohyoid muscle appears as an intermediate to low signal intensity structure (typical of skeletal muscle).

    • T2-weighted images:

      • Normal muscle demonstrates relatively low signal intensity, but increased signal may indicate edema or pathology.

    • STIR (Short Tau Inversion Recovery):

      • Muscle appears with low signal intensity; any edema, inflammation, or injury would appear hyperintense (bright) compared to normal muscle tissue.

  • CT Appearance:

    • On CT scans, the thyrohyoid muscle is visualized as a soft-tissue density structure between the thyroid cartilage and hyoid bone, distinguishable from adjacent fat and air spaces in the neck.

MRI images

Thyrohyoid Muscle mri axial image