In the vast majority of patients presenting with Raynaud's Phenomenon (R.P.) in the hands the condition is bilateral and often symmetrical, whether primary without any arterial disease, or secondary to some digital or more proximal arterial occlusive condition. Unilateral involvement is relatively rare and is often a sinister condition, and its presence cause must be determined and, if possible, dealt with. In this paper those cases associated with thoracic outlet abnormality are discussed, and those following iatrogenic injuries of the brachial artery are mentioned briefly.
