Hippocrates 
On Injuries of the Head [EPUB ebook] 

Men’s heads are by no means all like to one another, nor are the sutures of the head of all men constructed in the same form. Thus, whoever has a prominence in the anterior part of the head (by prominence is meant the round protuberant part of the bone which projects beyond the rest of it), in him the sutures of the head take the form of the Greek letter tau, T; for the head has the shorter line running transverse before the prominence, while the other line runs through the middle of the head, all the way to the neck.