“…Measurements indicate a gradual lateral reduction in frontalis muscle thickness from approximately 1.80 mm, identified at the intersection of the pupil’s midline with the horizontal plane connecting the metopion and glabella, to about 1.61 mm at the juncture aligned with the lateral canthus. Further laterally, at the convergence with the line from the lateral orbital rim and the aforementioned horizontal plane, the thickness diminishes to a mere 0.11 mm [ 46 , 47 , 48 ]. One study identifies that motor endplates, essential for motor function, are predominantly located in the middle and upper portion of the frontalis [ 35 ].…”