An explanation of Dr. Davis's craniotomy forceps.

Date:
[1820]
Catalogue details

Licence: Public Domain Mark

Credit: An explanation of Dr. Davis's craniotomy forceps. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    nffium or os coccygis; the shanks of both blades of the instrumen^ J being diverted at the curve from the axis of the brim of the pelvi/| to that of the lower part of the vagina. i ’ a b.—Tliis dotted line gives the length of the external blade of’ the double curved forceps, and measures thirteen inches. c d.—This dotted line gives the distance of the shank of the ex- ternal blade at the curve; c the thickness of the shank, inclusive from the strait line a b. It measures one inch and a half. ef.—This dotted line gives the distance of the shank of the in- tern^ blade at the curve e, from the strait line h i. the thickness of the shank inclusive, and measures two inches. g.—The perforation in the handle of the external blade to receive the brass nut, as described in Fig. 1. of the c^posite handle. N.B. This contrivance is intended to be common to both forms of the instrument. Fig. 3.—This figure is given to convey an idea of the dimensions of the grasping surface of the external blade. a b.—The dotted line a b, being one inch and ^ in length, mea- sures the greatest breadth of this surface across its concavity; the line being understood to subtend its concavity. c d.—The line thus marked, expresses the production of the in- strument beyond its concavity in the direction of its length, and measures a quarter of an inch. The object of this contrivance is to remove any pendulous part of the os uteri out of the reach of the grasp of the instrument. e d.—This line is a measure of the length of the concavity and subtends it. Ths length of the subtending line is 3| inches. The teeth projecting from the deepest part of the concavity, are a quarter of an inch long. Those in the shallower parts of the spoon, are progressively shorter as they approacli the brim; it being necessary for all, for the reason which has been already stated to be under the actual level of the brim. Fig. 4.—This figure is given to represent the convex surface of the internal blade. a b.—A strait line, which measures 1 inch, aiid gives the greatest breadth of this blade. c d.—A curved line drawn from the commencement of the con- vexity, where the shank begins to expand into blade, to its termi- nation at tlie top of the blade. This line is supjwsed to be a curve, following a curve of the grasping part of the instrument, and mea- sures 3f inches. The perforations on the convex surface, which are very well re- presented in the engraving, are intended to receive the teeth of the opposite blade. The vacant spaces between tlie perforations arc made rough, after the manner of a rasp, in order to prevent the slipping of this blade along the polished interior of the foetal skull.