The Overlooked Sad Face Expression: Understanding the Omega Sign in Botulinum Toxin Treatment.

[INTRODUCTION] Botulinum toxin injections are a popular cosmetic treatment for smoothing wrinkles. Recent trends emphasize not just wrinkle reduction but also the correction of facial expressions that convey emotions. Among these, the sad face expression, associated with the omega pattern, is often overlooked despite its significant role in emotional expression.

[METHODS] This study explored the anatomy and muscle activity related to the sad face expression, focusing on the occipitofrontalis, corrugator supercilii, depressor supercilii, procerus, and orbicularis oculi muscles. A new classification system was developed to categorize this expression based on patient control and muscle strength.

[RESULTS] The study found that the omega pattern is produced by the interaction of specific facial muscles, with three types of patient muscle control identified: automatic, controllable, and uncontrollable gestures. The visibility of the sad face expression varies among individuals due to differences in muscle strength and control.

[CONCLUSION] Incorporating the assessment of the sad face expression into pretreatment evaluations can enhance the effectiveness of botulinum toxin treatments by addressing both aesthetic and emotional aspects of facial expressions.

[LEVEL OF EVIDENCE] V.