And in whichever way the circle has been made, the same excising chisel should cut away from the corrupted bone every scale-like layer until sound bone is left. Black bone hardly ever penetrates the whole thickness of the bone, but caries sometimes does so, and especially when the cranium is diseased. A test of this is also made by means of the probe, which when inserted into a cavity which has solid bone underneath finds some resistance because of this and is wet when it comes up. 6 If it finds a clear way, as it goes deeper between bone and membrane, it encounters no resistance and comes up dry; not because there is no harmful sanies within, but because this is spread over a wider area. If bone is diseased right through, whether it be black bone exposed by the trepan, or caries discovered by a probe, the use of the modiolus is generally out of place, because what goes down so deep must be more widely opened up. p5017 Then the trepan which I described second is to be used; and in order that it may not get too hot, it should be dipped repeatedly in cold water. But particular care must be taken when we have bored half through a bone consisting of a single layer,18 or through the upper layer of a bone of two layers; in the former the actual distance bored, in the latter the appearance of blood is the indication. Therefore the strap is then worked more gently and the left hand held up and moved away more often, and the depth of the borehole is to be examined in order that we may perceive just when the bone is being broken through anywhere, and not run the risk of injuring the cerebral membrane by the point; which causes severe inflammation with danger of d**h. 8 When boreholes have been made, the intervening partitions are to be excised in the same way but much more carefully, lest the corner of the chisel injure the aforesaid membrane; until a sufficient opening has been made to insert a guard of the membrane which the Greeks call meningophylax.19 This consists of a plate of bronze, its end slightly concave, smooth on the outer side; this is so inserted that the smooth side is next the brain, and is gradually pushed in under the part where the bone is being cut through by the chisel; and if it is knocked by the corner of the chisel it stops the chisel going further in; 9 and so the surgeon goes on striking the chisel with the mallet more boldly and more safely, until the bone, having been divided all round, is lifted by the same plate, and can be removed without any injury to the brain. When all this bone has been removed, the margins of the opening must be filed down p503smooth, and if any bone dust is sticking to the membrane it is to be removed. When the outer table has been removed, and the inner table left, it is not only the margins but also all the bone20 which is to be smoothed down, in order that skin may grow over it subsequently without harm; for when it grows over rough bone there is never sound healing, but it causes new pains. 10 What is to be done when the brain is exposed, I will describe when I come to fractures.21 If some of the inner table has been preserved, medicaments which are not greasy, such as are fitted for recent wounds, are to be applied, and over that, unscoured wool soaked in oil and vinegar. In course of time flesh grows up from the bone and fills up the hollow made by the surgery. Also if any bone has been cauterized it separates from the healthy part, and between the sound and dead bone granulations form to throw off what has separated; and this is usually a thin and small splinter, which the Greeks call a scale.22
11 It may possibly even happen as the result of an injury, that bone, although neither fissured nor fractured, yet has its surface indented and roughened; when this happens scraping and smoothing suffice. These conditions, although mostly occurring in the head, are found also in the other bones, so that whenever the same thing happens the same procedure is to be followed. But for bones which are fractured, fissured, perforated or crushed, some special treatment is required, suited for particular cases, and some general measures which apply to the majority; of these I will proceed to treat, beginning with the said cranium.
4 1 Therefore after a blow on the head first we p505must enquire whether the patient has had bilious vomiting, whether there has been obscurity of vision, whether he has become speechless, whether he has had bleeding from the nose or ears, whether he fell to the ground, whether he has lain senseless as if asleep; for such signs do not occur unless with fractured bone; and when they are present, we must recognize that treatment is necessary but difficult. If in addition there is also stupor, if the mind wanders, if either paralysis or spasm has followed, it is probable that the cerebral membrane has also been lacerated; and then there is little hope. 2 But if none of these signs follows the injury, it is not even certain whether the bone is broken: and the first thing then to consider is whether he was struck by a stone or club or sword or other such weapon, and whether such a weapon was blunt or pointed, medium or heavy, used with much or little force; for the lighter the blow, the more easily we may conclude that the bone has resisted it. But the best plan is to make certain by exploration. Accordingly a probe should be introduced into the wound; it should be neither very fine nor pointed, lest it enter one of the natural sutures and give rise to a false belief in a fracture of bone; neither should it be too thick lest small fissures be missed. 3 When the probe comes into contact with the bone, if nothing but what is smooth and slippery is met with, it can be seen that the bone is intact; if any roughness is met with, at least where there are no sutures, it is a sign that the bone is fractured. Hippocrates,23 with great men's love of truth in great matters, has described how he had p507been deceived by sutures. 4 For shallow minds, because they have nothing, never belittle themselves; such a sincere confession of the truth befits a great mind which will still have many titles to greatness, and especially in performing the task of handing down knowledge for the advantage of posterity, that no one else may be deceived again by what has deceived him. But my regard for the memory of a great teacher has somehow led me into this digression. 5 Now a suture may possibly deceive just because it is rough too; so that although there is really a fissure, yet we may take it to be a suture, where it is likely that there is one. Therefore we must not be deceived just by this; the safest way is to lay bare the bone. For as I have stated above,24 sutures are not always in the same position, and a natural union of bone and a fissure from injury may coincide, or the fissure may be close by. 6 Therefore sometimes when the blow was severe, although nothing is detected by the probe, it is still best to open the place up. And if even then no fissure is visible, ink25 is to be applied over the bone, then it is to be scraped with a chisel; for a fissure will retain the blackness. It may even happen that the blow may have been upon one part of the head, and fracture at another. Thus if anyone has been heavily struck and bad signs have followed, and no fissure has been found in the part where the scalp has been wounded, it is worth while to examine whether some other part is softer and swollen, and to lay it open; then perhaps fissured bone may be found there. 7 Even if it be uselessly incised, the scalp heals without much trouble. A fractured bone unless it is treated causes severe inflammations, p509and is treated afterwards with greater difficulty. Rarely, but now and then, it happens, however, that whilst the bone remains whole and sound, yet within the skull a blood-vessel in the cerebral membrane has been ruptured by the blow and some blood has escaped, and this having formed a clot, causes great pains, or sometimes obscures vision. But generally the pain is directly over the clot, and when the scalp at that point is incised, the bone is found to be pallid; if so, that bone also is to be cut out.
8 But for whatever cause this treatment is necessary, if the scalp has not been laid open sufficiently, it must be incised more widely until the injury is well in view. In doing so we must see that none of the fine inner membrane covering the skull, under the scalp, remains over the bone; for whenever this is lacerated by the chisel or trepan it causes severe fevers with inflammations, and so it is better to raise it wholly off the bone. 9 If there is a cut as part of the wound we must take it as it is; if we have to make it, the best incision is generally that which is formed by two lines in the shape of the letter X; next the scalp is raised by cutting under each of the little tongues. When doing this if bleeding takes place it must be checked by the application of a sponge saturated with vinegar from time to time, also it must be absorbed by swabs of dry lint and the head must be raised higher. There need be no anxiety unless it comes from among the muscles covering the temples; but there also this is the safest method of dealing with it.