Date of this Version
University Studies, Vol. XVI October 1916 No·4
For a number of years I have been interested in the arterial variations which have been encountered in my dissecting rooms. Notes have been made of these abnormalities and the literature describing similar conditions has been gradually collected. The more recent textbooks in anatomy devote little space to the subject of arterial variations and the classic works which have reviewed the field are no longer readily consulted; then, too, new facts have been added to our knowledge of arterial development since the most recent of the latter were published. In view of these facts it has seemed worth while to assemble the cases I have collected from the various sources and classify them according to our present knowledge of development.
I wish to take this opportunity to express my thanks to Doctor W. F. Whitney, curator of the anatomical museum at Harvard Medical School, for placing the splendid collection of the Warren Museum at my disposal for study. In the later pages I have used the results of my study freely, referring to the various anomalies as from the Warren Museum. The following does not purport to be the entire list of all cases reported, for it was not possible with the library facilities and time I had at my disposal to consult all the works that might contain a record of such variations, but I believe a sufficient number have been collected on which to base reliable conclusions of the scope and possibly relative frequency of such abnormalities. The bibliography at the end of this study includes not only the cases referred to in the body of the work but, in addition, many titles which I was unable to consult but which came to me on good authority. I have included the latter believing that a full bibliography on any subject has a distinct value of its own. In this study I have confined the observations to those anomalies directly related to the aortic arches and the ventral aorta. In many cases the factor which has produced these variations seems to have influenced the development of the heart; since, however, no constant relationship could be discovered between the heart anomalies and those of the arches, I will reserve the study of the heart for a future paper. All cases which might be considered to be the result of known pathological processes have been excluded. Arterial variation is but one of many irregularities encountered in the human body and in order to appreciate it fully we must consider the subject of variation as a whole, otherwise we may be inclined to think that arterial variations have a significance and perhaps an importance greater than any other anomalies encountered.