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Show OPERA'IION 01" TRBPA N, OPERATIOS or mama. CHAPTER X1. 313 responding part has violently been depressed, I must conclude that the edge which presses on the dura mater is from the brittleness of the inner table, rougher, and armed with more sharp spiculze than that which I feel with my finger. or THE OPERATION or TREPAIN‘. [rue 'IKEPHINE is applied, 1. To prevent the depress ed and irregular bone from becoming a source of irritation to the membranes, and consequently to the brain itself ; the effects of which we have already explained. 2. To remove the dead portions of the bone, when the dura mater has separated from it, and matter lies upon that membrane. 3. To evacuate blood efl‘used betwixt the bone and dura mater. ""Mrnm "W. 1 i. To enable us to raise great depressions of the skull, which lililitliktl l‘i‘d F are oppressing the brain. Let us never forget that cutting down the integuments, i perforating the skull, and laying bare the dura mater, forms a very serious and dangerous wound, which is not to be risked, This sketch demonstrates the state of the part. A, the de- pressed bone. B B, the circle of the skull in its natural position. I affirm that there is great danger of the dura mater being irritated to suppuration or ulceration, from that point of bone at C ; and I always endeavour to judge of the sharpness of the depressed edge, before I advise the use of the he phine. In a fracture of this kind, I conceive that, cwtcris paribus, there is much less chance of its irritating the membranes. unless when a more pressing danger requires it. Simple as this injunction may appear, it seems to be often necessary. When there is fracture and depression, without any urgent symptoms, the general rule is to trust to a natural process for relief. I must say, however, that by the concurring opinion of several eminent men, this rule may be carried too far, and this although I look upon the operation of trepan as a very sew nous injury. If it be said, that the danger of oppressing the brain should not induce the surgeon to operate, and that to perform trepafl, in order to raise the bone which seems to threaten, or to cause oppression, is to act from a needless alarm-I should answer, that it is not upon the footing of this danger that I rest my opinion. I know that it takes a very deep depression to oppress the brain. But what I rely upon is this, that when I feel a rough edge of the skull, from which the cor- A A A, the natural circle of the cranium. B, the angle of depression, which, with a greater degree of depression than the last, does not present so sharp an edge to the dura mater, and consequently is not so dangerous. And here I am naturally led to remark on the subject of bleeding in cases of trepan, that as in inllammations of the lungs our safety is in bleeding, so is it in this case. Bleeding acts in a two-fold way ; by subduing the inflammatory action of the circulating vessels; and at the same time directly, by VOL. I. a ? WON! M09 |