T R E A T I S E
O F
Chirurgical Operations.
C H A P. I.
Of the Operation of the Trepan.
This Operation is to be perform'd, when it is inferr'd from the Signs of which we have already given a particular Account, that some Matter is diffus'd over the Dura Mater. The Trepan must not be us'd in the Sinus Superciliares, by reason of their Cavity; nor in the Sutures, in regard of the Vessels that pass thro' 'em; nor in the Temporal Bone without great necessity, especially in that part of it which is join'd to the Parietal-Bone, lest the end of this Bone shou'd fly out of its place, since it is only laid upon the Parietal; nor in the middle of the Coronal and Occipital-Bones, by reason of an inner
Prominence wherein they adhere to the Dura Mater; nor in the Passage of the Lateral Sinus's that are situated on the side of the Occipital.
If the Fissure be very small, the Trepan may be apply'd upon it, altho' it is more expedient to use this Instrument on the side of the Fissure in the lower part; neither is the Trepan to be set upon the Sinkings; and if the Bones are loosen'd or separated, there needs no other trepanning than to take 'em away with the Elevatory.
The Operation must be begun with Incision, which is usually made in form of a Cross, if the Wound be remote from the Sutures, and there are no Muscles to be cut, and in the shape of the Letter T. or of the Figure 7. if it be near the Sutures, so that the Foot of the 7. or of the T. ought to be parallel to the Suture, the top of the Letter descending toward the Temples; it is also made in the middle of the Forehead. If it be sufficient to make a longitudinal Incision in the Forehead; its Wrinkles may be follow'd, and there will be less Deformity in the Scar; but it is never done Crosswise in this Part, and the Lips of the Wound are not to be cut. If an Incision be made on the Muscle Crotaphites, and on those of the back-part of the Head, it may be done in form of the Letter V. the Point of which will stand at the bottom of the Muscles; nevertheless it is more convenient to make a longitudinal Incision, by which means fewer Fibres will be cut; and it is always requisite to begin at the lower part, to avoid being hindred by the Hæmorrhage.