"EFFORT" thrombosis of the axillary, subclavian and, occasionally, brachial veins, although occurring infrequently, may be the consequence of either severe or unaccustomed exertion. This report is an analysis of 72 cases, 16 of which I have collected and 56 of which are assembled from a partial review of the literature1 for the past ten years. "Effort" thrombosis was first reported in 1884 by von Schrötter.2 By 1920, Cadenat3 was able to collect 27 cases. Paggi,4 in a review of the literature, found only 74 cases reported up to July 1933, and Matas1r in 1934 was able to cite 100 such cases. Veal, in 1940,5 reviewing the literature for the last fifty years, was able to collect less than 150 cases and reported 17 of his own. His statistics are, however, subject to qualification, since he includes types of thrombosis other than "effort" thrombosis in