A total of 136 patients with a compression syndrome of the upper limb were examined systematically by selective dynamic angiography as developed by the Hôtel-Dieu Hospital in Montreal. The method consists of given multiple injections of a contrast medium with the patient's arm in thirteen different positions. This retrospective study demonstrated that this method carries very little risk and is well-tolerated by the patients. Conclusions are drawn from a comparative statistical analysis of the angiographic results and the therapy chosen. The practical value of the examination is not to confirm the anatomical site of the compression but to evaluate the characteristics of the stenosis before a decision is made whether to operate. In this respect, the positions in which the patient is sitting down and the arm is in abduction are those in which a difference is found between those patients operated upon and those given medical treatment, which is a point in favour of this particular procedure.