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Auricularis anterior muscle

The auricularis anterior muscle is a thin, fan-shaped muscle located anterior (in front) to the auricle (external ear). It is one of the three auricular muscles, along with the auricularis superior and auricularis posterior, and is the smallest of the trio. Although vestigial in humans and minimally functional, it contributes to subtle movement of the ear and is more pronounced in some individuals. The muscle is superficial, lying just beneath the skin and above the temporal fascia.

Synonyms

  • Anterior auricular muscle

  • Auricularis anticus

Function

  • Weakly draws the auricle forward (anterior movement of the ear)

  • Contributes minimally to ear positioning and facial expression

Nerve Supply

  • Supplied by the temporal branch of the facial nerve (cranial nerve VII)

Artery Supply

  • Supplied primarily by branches of the posterior auricular artery and superficial temporal artery

Vein Supply

  • Venous drainage through the superficial temporal vein and posterior auricular vein

MRI Appearance

  • T1-weighted:

    • The posterior band remains hypointense (dark/low signal), as fibrocartilage contains little fat or free water.

    • Provides good anatomical detail of disc position relative to bone and adjacent soft tissue.

  • T2-weighted:

    • The posterior band is hypointense (dark/low signal), in contrast to the hyperintense (bright) joint fluid.

    • Distinct from inflamed or edematous tissues, which would be brighter.

  • STIR (Short Tau Inversion Recovery):

    • The posterior band appears hypointense (dark/low signal), as STIR suppresses fat and highlights fluid/edema, but fibrocartilage stays dark.

CT Appearance

  • Appears as a thin, soft-tissue density anterior to the auricle, superficial to the temporal fascia.

  • Difficult to distinguish unless there is pathology or marked hypertrophy.

Summary Points

MRI images

Auricularis anterior muscle axial image

MRI images

Auricularis anterior muscle coronal t2 image