What is the difference between dynamic and static wrinkles?

When thinking about anti-wrinkle treatments (botulinum toxin aka Botox), it is important to understand the difference between the two main types of lines that we get

Dynamic lines appear when we make facial expressions, for example, the lines across our forehead when we look surprised, the lines between our brows when we frown and the lines from the corner of our eyes when we smile. Anti-wrinkle injections work on this type of line, by relaxing and smoothing the muscles so that the skin lies flat over it.

Static lines usually start off as dynamic lines, but are present even when the face is at rest. They start to form as we lose collagen and elastin, meaning that skin is less plump and able to bounce back. Although anti-wrinkle injections do not specifically treat static lines, there is often a softening of them as a result of the muscles relaxing. Other treatments such as medical grade skincare, chemical peels, dermal fillers and/or laser treatments may be recommended.

In the pictures is one of my clients who I treated with anti-wrinkle injections. You can see that the dynamic lines in the forehead are no longer present when she raises her eyebrows and the static lines have also softened when the face is at rest.