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Superficial head of medial pterygoid muscle

The superficial head of the medial pterygoid muscle is one of the two distinct anatomical portions of the medial pterygoid muscle, a key muscle of mastication situated in the infratemporal fossa of the skull. It is smaller than the deep head and lies anterior and superficial to it. The superficial head assists in the elevation and side-to-side movements of the mandible, playing a significant role in chewing. Its unique anatomical origin, insertion, and vascular as well as neural supply distinguish it from other masticatory muscles, and its imaging features are relevant in both clinical diagnostics and surgical planning.

Synonyms

  • Superficial portion of medial pterygoid muscle

  • Pars superficialis musculi pterygoidei medialis (Latin)

Function

  • Elevation of the mandible (jaw closure)

  • Assists in small, side-to-side (lateral) movements of the jaw during mastication

  • Aids in protrusion of the mandible (with other muscles)

Origin

  • Maxillary tuberosity (the posterior aspect of the maxilla)

  • Pyramidal process of the palatine bone

Insertion

  • Medial surface of the angle of the mandible (lower part of the ramus of mandible)

Nerve Supply

  • Medial pterygoid branch of the mandibular nerve (V3), a division of the trigeminal nerve (cranial nerve V)

Artery Supply

  • Branches from the maxillary artery (main supply)

  • Contributions from the pterygoid branches of the facial artery

Vein Supply

  • Pterygoid venous plexus

MRI Appearance

  • T1-weighted images: Appears as an intermediate to low signal intensity structure, distinguishing muscle from surrounding fat and connective tissue.

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

  • STIR (Short Tau Inversion Recovery): Muscle shows low signal intensity in healthy tissue; hyperintensity is seen if there is edema, inflammation, or acute injury.

CT Appearance

  • The superficial head appears as a soft tissue structure of muscle density, anterior and superficial to the deep head of the medial pterygoid, adjacent to the medial mandibular angle

MRI images

Superficial head of medial pterygoid muscle mri axial image -img-00000-00000