Anatomy of the Skull and Its Utilities

As for the useful function of the set of skull bones, it consists in the fact that these bones are armor for the brain, which covers it and protects it from disasters. And the benefits of the skull being made from many pieces and more than one bone are divided into two groups. One group has to do with the bone itself, and the other group has to do with what is contained in the bone. The first group is divided into two utilities. One of them is that if damage occurs to part of the skull - a fracture or a caries infection, it will not necessarily spread to the entire skull, as it would if it consisted of one bone. Second: in one bone there is no difference in terms of hardness and softness, looseness and density, thinness and thickness - the difference that the circumstances require, which we will talk about shortly. Another group combines benefits that are carried out by seams. Some of them relate to the brain itself, for the sutures open a way and a path for the vapors released in the brain and cannot pass through the very bones to leave the brain because of their thickness, and the brain is thus purified by releasing these vapors.

Another usefulness of sutures relates to the threads of nerves emerging from the brain that grow in various parts of the head: the sutures serve to give them passage. Two utilities are common to the brain and to two other things. One of these benefits relates to the vessels and arteries penetrating into the head - the sutures serve to give them passage. Another benefit relates to the thick, heavy membrane of the brain: parts of it adhere to the sutures, so that it rises above the brain and does not press on it.

The natural shape of this bone is round, and this is due to two circumstances and two utilities. One of them relates to the inside of the skull. The fact is that a round figure is larger in area compared to what other figures bounded by straight lines can cover if their sizes are equal.

Another usefulness relates to the outer part of the skull. A round figure does not suffer as much from blows as an angular figure does. Being round, the skull was created at the same time elongated in length, since the places from which the brain nerves grow are located along, which was necessary so that they would not be squeezed. There are two projections on the skull, one forward and one back, that are supposed to protect the nerves that run down on either side. A skull of this shape has three true sutures and two false sutures. The first seams include a seam in the form of an arc, which merges with the forehead in this way and is called

“coronal seam”, as well as a straight seam running along the middle of the head. This suture alone is called sagittal, and when it is considered in connection with the coronal suture, it is called “trochanteric.” In shape it is similar to an arc, in the middle of which there is a straight line, similar to a perpendicular - like this:. The third seam is common at the back of the head⁶ and at its base. It has the shape of an angle, the apex of which is adjacent to the end of the sagittal suture, and is called lambdoid, as it resembles the letter “l” in the writing of the Greeks. In connection with the two previous seams, its shape appears as follows:

As for the false seams, they run along both sides of the head, parallel to the sagittal seam. They do not go completely into the bone and are therefore called scaly. When these seams are connected 6 with the first three true seams, their general appearance is as follows: > >

This is the natural shape of the head. As for unnatural head shapes, there are three of them. One of them is when the anterior protrusion of the skull is missing then there is no coronal suture among the seams on the head. The second case is when the rear projection is missing then the lambdoid suture is missing on the head. In the third case, both protrusions on the head are missing at once and the head is made like a ball - it is the same in both length and width. Says the most worthy of physicians, Galen: “Since with this shape of the head the distances are equal, then in fairness the distribution of the sutures should also be equal. However, in the first shape of the head, the seams are distributed like this: along - one seam, across - two seams, and here there is one seam along, and across - also one seam in this case, the transverse seam stretches across the width in the middle - from ear to ear in the form of an X, just as the longitudinal seam stretches along the middle.” This worthy man also says: “And the head cannot have the fourth unnatural variety of shape, in which the length would be less than the width, without the cavities containing the brain or the size of its body being reduced to some extent, and this is contrary to the requirements life and correctness of addition.” Thus, Galen confirms the words of Hippocrates, who established only four forms of the skull and nothing more. Know this.