BACKGROUND: Our society's focus on facial beauty has recently expanded to ear beauty, with an increase in related complications. We aimed to elucidate the mechanisms underlying complications associated with ear filler injections by exploring the course of auricular blood vessels through cadaver anatomical and imaging examinations. METHODS: Thirty cadavers underwent arterial perfusion with red latex, and computed tomography was utilized for 3D reconstruction to analyze the relations between arteries, nerves, and lesions in the auricular area. RESULTS: Extensive communication between the posterior auricular artery (PAA) and the superficial temporal artery was detected. The PAA produced three to four branches retroauricularly, which further produced secondary branches toward the helix. Some PAA branches entered the skull near the facial nerve through the stylomastoid foramen. CONCLUSIONS: The ear filler may embolize the ophthalmic artery through multiple communicating branches of the superior auricular artery as well as arteries in the temporal region. It may also embolize arteries via the secondary branches of the PAA, causing skin necrosis. Possible causes of associated facial paralysis include embolism of the stylomastoid artery and direct facial nerve compression by hyaluronic acid. LEVEL OF EVIDENCE IV: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .