Filler injection into the glabella is well known to be a highly dangerous procedure due to the high risk of embolism and intravascular injection.

Although it is conventional practice to insert the cannula into the middle of the forehead to perform injections into the glabella or radix, vascular structures can be observed in this region during anatomic dissection procedures.

The aim of this study was to characterize the blood vessels around the forehead midline in order to provide crucial anatomic information for ensuring the safety of noninvasive procedures involving the forehead and glabella.

Ultrasonography image scanning was performed at the following 4 points on the forehead midline: trichion (P1), metopion (P2), halfway point between metopion and glabella (P3), and glabella (P4). The courses and locations of vessels were identified and classified according to their proximity to the forehead midline.