Celsus, De Medicina
W. G. Spencer, Ed.

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3 Now bone is excised in two ways; if the damaged part is very small, with the modiolus, which the Greeks call xoineiki/j; if more extensive by means of trepans. I will describe the use of both. The modiolus is a hollow cylindrical iron instrument with its lower edges serrated; in the middle of which is fixed a pin which is itself surrounded by an inner disc. The trepans are of two kinds; one like that used by smiths, the other longer in the blade, which begins in a sharp point, suddenly becomes larger, and again towards the other end becomes even smaller than just above the point. When the disease is so limited that the modiolus can include it, this is more serviceable; and if the bone is carious, the central pin is inserted into the hole; if there is black bone, a small pit is made with the angle of a chisel for the reception of the pin, so that, the pin being fixed, the modiolus when rotated cannot slip; it is then rotated like a trepan by means of a strap. The pressure must be such that it both bores and rotates; for if pressed lightly it makes little advance, if heavily it does not rotate. It is a good plan to drop in a little rose oil or milk, so that it may rotate more smoothly; but if too much is used the keenness of[p. 499] the instrument is blunted. When a way has been cut by the modiolus, the central pin is taken out, and the modiolus worked by itself; then, when the bone dust shows that underlying bone is sound, the modiolus is laid aside. But if disease is too extensive for the modiolus to cover, the operation must be carried out by the trepan. With this a hole is made exactly at the margin of the diseased and sound bone, then not very far off a second, and a third, until the whole area to be excised is ringed round by these holes; and here also the bone dust shows how deep the trepan is to go. Next the excising chisel is driven through from one hole to the other by striking it with a mallet, and cuts out the intervening bone, and so a ring is made like the smaller one cut by the modiolus. 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. 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.[p. 501] 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, 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 death. 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. 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; 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[p. 503] smooth, 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 bone 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. What is to be done when the bain is exposed, I will describe when I come to fractures. 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.

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.