Unlike dermal fillers, which are injected below the skin to add contours and volume, anti-wrinkle injections act directly on the nerves which control muscular contractions. Botulinum toxin, the substance used for anti-wrinkle injections, suspends the connection between the nerves and facial muscles in the treated area. This reduces the activity of facial muscles often responsible for wrinkles, such as frown lines, furrowing between the brows, and crow’s feet from squinting, for example. While this suspension of movement does not directly contour the face as dermal filler does, it can help to soften features and reduce the size of large muscles that make the face appear angular or rigid. The muscles of the midface are a good example, as these can become enlarged from chewing or clenching, and result in a squarer jawline. Using anti-wrinkle injections can soften the jawline by relaxing these midface muscles, therefore decreasing their size and prominence.