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Styloglossus muscle

The styloglossus muscle is one of the four extrinsic muscles of the tongue, playing a crucial role in tongue movement. It is slender, cylindrical, and arises from the styloid process of the temporal bone, extending downwards and forwards to insert into the lateral aspect of the tongue. The styloglossus is essential for retracting and elevating the tongue, facilitating swallowing and speech. Its anatomical features and neurovascular supply are clinically significant, particularly in head and neck imaging and surgeries.

Anatomy and Description:

  • The styloglossus muscle is a paired, narrow muscle.

  • It is one of the extrinsic tongue muscles, along with the genioglossus, hyoglossus, and palatoglossus.

  • The muscle is located in the lateral pharyngeal wall, extending from the base of the skull to the side of the tongue.

Origin:

  • Arises from the anterolateral surface of the styloid process of the temporal bone.

  • Also partially arises from the stylomandibular ligament.

Insertion:

  • Fibers pass downward and forward.

  • Insert into the side and inferior aspect of the tongue, interdigitating with the fibers of the hyoglossus muscle.

Function:

  • Retracts the tongue (draws it backward).

  • Elevates the sides of the tongue.

  • Assists in swallowing and speech by shaping and positioning the tongue.

Nerve Supply:

  • Supplied by the hypoglossal nerve (cranial nerve XII).

Artery Supply:

  • Primarily supplied by the lingual artery (a branch of the external carotid artery).

  • Additional minor supply from the ascending pharyngeal artery.

Vein Supply:

  • Drained by the lingual vein.

  • Venous blood ultimately drains into the internal jugular vein.

MRI Appearance:

  • T1-weighted images:
    The styloglossus muscle appears as a well-defined, intermediate to low signal intensity structure, similar to other skeletal muscles.

  • T2-weighted images:Normal muscle demonstrates relatively low signal intensity, but increased signal may indicate edema or pathology.

  • STIR (Short Tau Inversion Recovery):
    The muscle appears with low to intermediate signal intensity. Edema or pathology would show as increased signal.

CT Appearance:

  • Appears as a soft tissue structure of slightly higher density than surrounding fat.

  • Not typically well-differentiated unless there is pathology or contrast enhancement.

MRI images

Styloglossus muscle mri axial image -img-00000-00000