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Temporalis muscle (face)

The temporalis muscle is a broad, fan-shaped muscle located on the side of the head, forming a prominent part of the temporal fossa. It plays a crucial role in mastication (chewing) by elevating and retracting the mandible (jawbone). Its robust structure and distinctive shape make it easily recognizable in anatomical studies and imaging. Understanding the temporalis muscle is essential for clinicians, radiologists, and students, particularly when evaluating pathologies involving the masticatory system or temporal region.

Function:

  • Primary muscle involved in mastication (chewing)

  • Elevates the mandible (closes the jaw)

  • Posterior fibers retract the mandible

Origin:

  • Temporal fossa (area on the lateral skull above the zygomatic arch)

  • Temporal fascia (dense connective tissue covering the temporalis muscle)

Insertion:

  • Coronoid process of the mandible (anterior border, medial surface, and apex)

  • Anterior border of the mandibular ramus

Nerve Supply:

  • Deep temporal nerves (anterior and posterior branches)

  • Branches of the mandibular division of the trigeminal nerve (cranial nerve V3)

Artery Supply:

  • Deep temporal arteries (anterior and posterior)

  • Branches of the maxillary artery

Vein Supply:

  • Deep temporal veins

  • Drain into the pterygoid venous plexus

Imaging Features

MRI Appearance:

  • T1-weighted images:

    • Temporalis muscle appears as intermediate (isointense) signal compared to other skeletal muscles

  • T2-weighted images:

    • Shows intermediate to low signal intensity

    • Edema, inflammation, or pathology will appear as high (bright) signal

  • STIR (Short Tau Inversion Recovery):

    • Suppresses fat, highlighting edema or pathology as hyperintense (bright) areas

    • Normal muscle remains low to intermediate signal

CT Appearance:

  • Appears as a well-defined, homogenous soft tissue structure overlying the temporal bone

MRI images

Temporalis muscle mri axial image -img-00000-00000

MRI images

Temporalis muscle mri sagittal image -img-00000-00000