It has not been found possible in the arrangement of these dissections to classify them under the usual headings of Head and Neck, Upper extremity, Abdomen, and Lower extremity, because many of them would have been included under two or even more of these: in fact, they have often been specially planned with this object, so as to include the border lines of parts which, as they belong strictly neither to one nor the other dissector, are often neglected entirely. Nevertheless, this order has been followed for the most part, and in cases where a dissection involves partly one part and partly another, it has as far as possible been used as an intermediate link between the two. It is taken for granted that the student should have carefully dissected the whole body through before he turns his attention to special dissections. The steps outside the usual routine that are necessary to be taken to expose different structures, form a special feature of the higher anatomical examinations, and, indeed, are not absent from the more ordinary ones, and my experience of the past four years has shown me that students are often nonplussed as to the mode in which questions of this sort should be answered: it is to meet this difficulty, and also to assist those who may wish to carry their anatomical knowledge further than the usual dissecting-room course would allow them, that this work has been published.
I am thoroughly convinced that it is well nigh impossible to accurately answer many of the questions that are asked in the higher examinations, except they have previously been worked out practically, and am strongly of opinion that special arrangements should be made to meet the requirements of candidates for these tests. If a subject were allotted to four instead of eight dissectors, I think, by mutual arrangement and consultation between themselves, they might each of them perform many special dissections, and might collectively work out many others.
The present manual is the result of special work during the conduct for the past two years of the anatomical class for the first M.B. examination of the University of London. I have been greatly assisted by Messrs. W. A. Lane and J. A. P. Price, Assistant Demonstrators at Guy's Hospital, and to them I desire to express my great obligations for thorough and painstaking work in the pro-section for this class.
The principle that has been followed throughout, has been to perform the dissection with the least possible destruction of surrounding parts compatible with the full exposure of the structure under consideration. The skin incisions have been carefully planned with this object, and I may incidentally remark that this is often one of the most difficult steps of the dissection, and that further, owing to the retraction of the divided skin, the surface exposed will always be greater than that strictly included between the lines of incision. It will frequently happen that there are several preliminary steps to be taken before the actual point of the question is reached. Thus in a dissection to expose the Thoracic duct, the opening of the Thoracic and Abdominal cavities may fairly be considered as not an essential part of the dissection, whilst in one to display the Internal Mammary Artery, a detailed account of the Thoracic and Abdominal parietes is evidently required. Students are often puzzled to know whether they are to consider such cavities as opened, or whether they are to write down every separate structure they divide in the course of the dissection. It is difficult to give an absolute answer, but in the absence of specific information from the examiner himself, much will depend upon the amount of time allowed them to write their paper. It may, however, be taken for granted that nothing but naked-eye anatomy is required.
The plan that has been followed in arranging and writing out the various dissections is this:—
1. The position of the body, or part, is indicated.
2. The requisite skin incisions have then been stated carefully.
3. The dissection has been divided into stages numbered I., II., III., etc, and the different steps of each stage have been indicated by the small letters a, b, c, d, etc.
4. After each stage short accounts numbered 1, 2, 3, 4, etc, of the structures exposed have been given, following as far as possible some definite direction, as from above downwards, or from side to side, and taking them in the order of bones, muscles, arteries, veins, nerves, etc. The student should avoid giving a bare list: he is not required to describe each structure that may be exposed, but he should indicate the relative positions of parts succinctly and distinctly.
5. When a structure to be exposed lies in two or more distinct regions each has, in some cases, been taken separately and indicated by the capitals A, B, C. I am painfully aware of the imperfections of this work, but trust that as each dissection has been actually performed, want of accuracy will not be one of them. No doubt the absence of plates is a striking deficiency, but in the presence of the beautiful atlases of Professor Ellis, and more recently that of Mr. Godlee, I am strongly of opinion that these will not be found necessary. My object, however, has been mainly to supply a little manual within the reach of all, which may be a guide to actual dissecting-room work.
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