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Stylopharyngeus muscle

The stylopharyngeus muscle is a slender, longitudinal muscle of the pharynx located in the lateral wall of the oropharynx. It plays a vital role in swallowing by elevating the pharynx and larynx. As part of the inner longitudinal muscle layer, it is unique in its nerve supply and anatomical features, making it an important landmark in head and neck anatomy.

ANATOMY & GENERAL FEATURES

  • Long, thin muscle originating from the base of the skull.

  • Positioned between the superior and middle pharyngeal constrictors.

  • Lies medial to the stylohyoid ligament.

ORIGIN

  • Arises from the medial aspect of the styloid process of the temporal bone.

INSERTION

  • Passes downward and medially between the superior and middle constrictor muscles.

  • Inserts into the posterior border of the thyroid cartilage and the pharyngeal wall (some fibers blend with the constrictor muscles).

FUNCTION

  • Elevates the pharynx and larynx during swallowing and speech.

  • Assists in widening the pharynx to facilitate the passage of a food bolus.

NERVE SUPPLY

  • Supplied exclusively by the glossopharyngeal nerve (cranial nerve IX).

  • It is the only pharyngeal muscle innervated by the glossopharyngeal nerve; all others receive vagus nerve (cranial nerve X) supply.

ARTERY SUPPLY

  • Primarily supplied by the pharyngeal branches of the ascending pharyngeal artery (a branch of the external carotid artery).

  • Additional minor contributions from facial and lingual arteries.

VEIN SUPPLY

  • Venous drainage is via the pharyngeal venous plexus, which drains into the internal jugular vein.

MRI APPEARANCE

  • T1-weighted: Appears as intermediate-to-low signal intensity relative to surrounding soft tissues.

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

  • STIR (Short Tau Inversion Recovery): Demonstrates high signal intensity if pathology (edema, inflammation) is present, otherwise low-to-intermediate signal in normal muscle.

CT APPEARANCE

  • Appears as a thin, soft-tissue density band along the lateral wall of the pharynx.

  • Best visualized on contrast-enhanced CT as a muscle with moderate enhancement.

MRI images

Stylopharyngeus muscle mri axial image -img-00000-00000