The depressor supercilii muscle (DS) is a small but clinically relevant depressor of the glabellar region, whose morphology and independent existence remain debated. Precise knowledge of its variations is critical for optimizing botulinum toxin (BoNT) injections and surgical interventions. A total of 44 DS specimens from 22 embalmed Korean cadavers (10 males, 12 females; mean age, 72.1 years) were dissected. The DS was analyzed for overall shape, fiber orientation, and attachment sites, with classification into morphological subtypes. Bilateral symmetry was also assessed. Two major shapes were identified: wide fan- shaped (79.5%) and narrow band-shaped (20.5%). Fiber orientation was predominantly vertical (86.4%), with a minority displaying asymmetric (6.8%) or oblique (6.8%) trajectories toward the orbicularis oculi. Five insertion patterns were observed, ranging from exclusive eyebrow to exclusive glabellar attachment. Balanced dual insertion was the most frequent, with symmetrical patterns in 45.5% and asymmetrical patterns in 54.5% of cadavers. These findings support the DS as an anatomically distinct muscle exerting a primarily vertical downward pull on the medial eyebrow and glabella. The DS demonstrates consistent vertical orientation but variable morphology and attachment patterns, which may explain incomplete wrinkle reduction and asymmetry following standard BoNT injections. Recognition of DS variability highlights the need for individualized treatment strategies in both aesthetic and reconstructive practice.

KEY WORDS: Depressor supercilii muscle; Orbicularis oculi muscle; Glabella; Wrinkle; Botulinum toxin injection.