Why, When, and How to Treat Dynamic Forehead Lines with Botulinum Toxin Type A

Recent advances in the understanding of facial anatomy have contributed significantly to the refinement of injection techniques for the treatment of dynamic forehead lines. A comprehensive assessment of eyebrow shape, position, and the aging process is essential, as the latter are closely linked to the functional balance between the frontalis muscle and the upper facial depressors. Optimal outcomes also depend on the accurate determination of dosage per injection point, injection depth, and strategic distribution of injection sites within the frontalis, which should be carefully considered and tailored to the individual's anatomical characteristics and therapeutic goals-whether the aim is neuromodulation for muscle activity reduction or intradermal application for skin quality enhancement. A round table discussion session among three experienced international dermatology experts in aesthetic botulinum toxin type A was performed during a MERZ LATAM-sponsored medical education session. Recent insights in facial anatomy, including the precise location and distribution of motor endplates, as well as the direction of muscular force vectors during contraction; aging processes; and interindividual variability in facial musculature and mimicry patterns are discussed, and the results are described herein. These factors play a critical role in customizing personalized injection strategies and improving aesthetic outcomes in the treatment of forehead lines.