Book 8
1
First then comes the skull, concave internally, convex externally, on both aspects smooth, where it covers the cerebral membrane as well as where it is covered by the skin bearing hair; and it is in one layer from the back of the head to the temples, in two layers from the forehead to the vertex. Its bones are hard externally, but the inner parts which connect them together are softer, and between these run large blood-vessels which probably supply their nutrition. It is rare for the skull to be solid without sutures; in hot countries, however, this is more easily found; and that kind of head is the firmest and safest from headaches. As for the rest, the fewer the sutures, the better for the heads; and there is no certainty as to the number, or even as to the position of the sutures. Generally, however, there are two above the ears separating the temples from the upper part of the head: a third stretches to the ears across the vertex and separates the occiput from the top of the head. A fourth runs likewise from the vertex over the middle of the head to the forehead, sometimes ending at the hairy margin, sometimes dividing the forehead itself and ending between the eyebrows. Most of these are dovetailed, but those which cross over above the ears are bevelled off a little all along their margin so that the lower bones smoothly overlap the upper. Now the thickest bone in the head is behind the ear, where hair does not grow, probably on that very account. Under the muscles covering the temples is situated the middle bone which slopes outwards. But the face has the largest suture; it begins at one temple, passes across the middle of the orbits and nose to the other temple. From this suture two short sutures are directed downwards from the inner corners of the eyes; and the cheeks at their upper parts also have transverse sutures. From the middle of the nostrils or of the gums of the upper teeth, one suture runs back through the middle of the palate, another cuts the same palate transversely. These are the sutures found in most skulls.
