Forehead lines (forehead wrinkles) are located on the forehead area. They are either dynamic (only created by movements) or static (they exist even without movements). They are created as a result of contraction of a very thin muscle in the area which is called Fronto-occipital muscle. Some patients have a very deep lines in this area which indicates this muscle is very strong.
The pattern of this muscle is different in different clients. Some clients have these lines all the way from one side of the forehead to the other side. But some clients have them in a smaller area either in the centre of the forehead or only above the eyebrows. Here are the 4 distinct types of these lines: