In human anatomy, the forehead is an area of the head bounded by three features, two of the skull and one of the scalp.
The top of the forehead is marked by the hairline, the edge of the area where hair on the scalp grows.
The bottom of the forehead is marked by the supraorbital ridge, the bone feature of the skull above the eyes.
[1] Blood supply to the forehead is via the left and right superorbital, supertrochealar, and anterior branches of the superficial temporal artery.
"Animals, even the most intelligent of them,", wrote Samuel R. Wells in 1942, "can hardly be said to have any forehead at all, and in natural total idiots it is very diminished".