To excel in neurotoxin injections for glabellar frown lines, a profound understanding of facial anatomy is indispensable (See Reference Diagrams). The vertical lines in the glabella region are primarily caused by the contraction of the paired corrugator supercilii muscles, while horizontal lines result from the activity of the centrally located procerus muscle. The corrugator muscles have their origins on the supraorbital ridge of the frontal bone, extending to insert on the skin above the middle third of the eyebrow. On the other hand, the procerus muscle originates on the nasal bone and inserts onto the skin of the glabella or mid-forehead.
However, it’s crucial to recognise that facial anatomy is far from uniform, and subtle variations can manifest during facial animation. Notably, there are two distinct patterns of corrugator muscle positioning: one following a straight path along the brow and the other exhibiting a more vertical, V-shaped orientation. As practitioners, we must not rely on a single technique but, instead, “look through” the skin to visualize the muscles and their role in the formation of wrinkles during facial expressions.
