摘要

Objectives: This work aims to evaluate the various patterns for injecting Botulinum Toxin (BTX) into the Frontalis muscle and present evidence-based data related to each approach, assessing their scientific validity, safety, and indications. Learning Outcomes: • Gain an in-depth knowledge of the different injection patterns for Botulinum toxin injection into the forehead. • Understand the indications, effectiveness, and safety for each injection pattern. Introduction: Several patterns for injecting Botulinum Toxin (BTX) into the Frontalis muscle have been described, including the M-shaped pattern, the Horizontal pattern, the V-shaped pattern, the 2-row pattern, and the C-line related pattern (1). Patterns that emphasize brow lifting often aim to preserve the lateral Frontalis muscle or focus on the upper frontalis above the C-line, as described by Cotofana et al (2020). Materials / method: An extensive literature review pertaining to BTX injection in the forehead was conducted. Search terms included "Botulinum Toxin," “Frontalis muscle,” "Forehead," "Forehead injection patterns," " Frontalis muscle injection patterns," "Botulinum toxin injection patterns" and “complications”. Results: The M-shaped injection pattern seems to be commonly adopted. The C-line related pattern is promoted for its enhanced safety. The Horizontal pattern is believed to preserve the brow shape. Limited information exists regarding the V-shaped pattern, which is posited to reduce the incidence of brow ptosis. Conclusion: The current emphasis on safety favours the C-line related pattern to prevent ptosis. Nevertheless, injectors should familiarize themselves with the various patterns, understanding their respective advantages and disadvantages, as they might be beneficial in particular scenarios, such as resistant forehead lines or brows prone to ptosis.