Why Straight and Curved Platysma Morphologies May Produce Opposite Clinical Effects?

Lower-face and neck lifting with botulinum toxin A is usually explained as a release of the platysma's downward depressor pull. This explanation is useful but incomplete. The facial extension of the platysma is broad, variable, and often asymmetric, and its visible contraction pattern may be straight, straight-curved, or curved. This clinical commentary proposes that the platysma pattern is a major determinant of whether a neuromodulator-based lifting procedure succeeds, fails, or paradoxically worsens the apparent contour. In a straight or vertical-dominant pattern, the active platysma behaves clinically as a depressor vector acting on the mandibular border, oral commissure, and jowl. Selective weakening of this vector can improve the jawline by rebalancing it against elevators and static retaining structures. In a curved or posterior-dominant pattern, however, the fibers may contribute a backward or posterior retractive vector. When this vector is weakened indiscriminately, the treatment may remove a component of posterior support rather than simply release downward traction; the clinical result may therefore be minimal lifting, anterior soft-tissue collapse, worsened submental fullness, or more visible sagging. The practical implication is that platysma treatment should begin with a dynamic examination, not a fixed injection grid. Patients should be evaluated upright at rest and during maximum contraction, with the injector documenting the direction of skin motion, the location of active bands, and whether the dominant vector is vertical, mixed, or curved. Ultrasound can strengthen this assessment by confirming the superficial muscle, band thickness, gliding, and relationship to deeper structures. The commentary outlines an anatomical rationale, a pattern-based classification, and a conservative clinical algorithm for safer and more predictable jawline lifting.