No abstract

ONE FIGUREDuring routine observation in the dissecting-rooni, my attention has often been called to anomalies of the aortic arch, these anomalies particularly involving the subclavian artery or some of its components. Therefore it has seemed well to preserve data with the purpose of finding for the material at hand (whites and mixed negroes) the normal origin of the subclavian artery and the modes and frequency of variations. Important reports on these anomalies have been furnished by Quain ( '44), Tlioinson ( '93), Holzapfel ( '99), Geddes ('11) and Poynter ('16).The present study is based on records made by myself on 278 student dissections, 139 of each side. Such subjects as were dissected only on one side by students were dissected on the other side for thorax, neck, and shoulder by members of the laboratory staff. All records of whites and some of negroes were made a t the University of Wisconsin (1913-16), most of the records of negroes were made at the University of Mississippi (1917-22). The records thus cover a period of eight years. Of the 139 subjects examined 52 were whites, 37.5 per cent (43 males and 9 females), and 87 were negroes, 62.5 per cent (78 males and 9 females).I t seems best to present the origin of the subclavian artery as it is related to the origin of other aortic stems. 235

FIFTEEN FIQURESSince the brachial plexus in monkeys has not heretofore been examined in series large enough for statistical treatment, we feel that we are fortunate in being able to offer in the present report a thorough study of the plexus in Nacacus rhesus (Pithecus rhesus after Elliot, '13 ; Macaca mulatta after Miller, '33). This study is based on dissections of right and left plexuses in 150 specimens, i.e., a total of 300 plexus dissections. Each dissection and record are our own work, from which it follows that differences in manipulation, methods of recording, interpretation and other factors of personal equation, such as would arise from student dissections, are here eliminated.I n the same dissections the branches of the subclavian and axillary arteries have been fully exposed and recorded; these records, however, will be reserved for a separate report. The large amount of work required for these plexus-artery dissections will doubtless seem a formidable task, especially since much of it was done under magnification and with uniform care as to the smaller nerves and arteries. That such a project has called for long sustained effort we readily affirm.Yet where at first a single dissection required 4 or 5 days, it was eventually possible to complete two dissections in 1 day.Including many unforeseen interruptions, at least 15 months were devoted to this project. 223

No abstract

No abstract