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Topic

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Posterior auricular artery

The Posterior Auricular Artery is a small but important branch of the external carotid artery, supplying blood to the auricle (external ear), scalp behind the ear, and surrounding structures. Emerging just above the digastric and stylohyoid muscles, it courses posteriorly along the groove between the auricle and the mastoid process. Its clinical relevance lies in surgical, trauma, and radiological evaluations of the temporal and auricular regions.

Synonyms

  • Auricularis posterior artery

  • Arteria auricularis posterior (Latin)

  • PAA (abbreviation)

Function

  • Supplies blood to the auricle (external ear)

  • Provides vascular supply to the scalp posterior to the ear

  • Contributes small branches to the mastoid, facial nerve, and parotid gland

  • Important in reconstructive surgery and as a landmark in vascular imaging

MRI Appearance

  • T1-Weighted Imaging (T1WI):

    • Appears as a flow void (signal loss) due to rapidly flowing blood within the artery

    • Surrounding soft tissue and fat show normal signal intensity

  • T2-Weighted Imaging (T2WI):

    • Also typically seen as a flow void (signal loss)

    • Hyperintense perivascular structures such as fat may outline the vessel

  • STIR (Short Tau Inversion Recovery):

    • Vessel remains as a flow void against a background of suppressed fat signal

    • Useful for detecting vessel wall pathology or inflammation if present

  • Time-of-Flight (TOF) MR Angiography:

    • The artery is highlighted as a bright (high signal) tubular structure due to inflow effect

    • Allows visualization of vessel patency, caliber, and any abnormalities

CT Appearance

  • Non-contrast CT:

    • Not easily visualized directly unless enlarged or calcified

    • May appear as a small round/oval structure posterior to the auricle, close to the mastoid process

  • Contrast-enhanced CT (CT Angiography, CTA):

    • Clearly visualized as an enhancing (bright) tubular structure

MRI images

Posterior auricular artery mri axial image