In Raynaud's phenomenon, there is functional abnormal blood flow in the vessels of the forearm. While blood flow is slow in the radial and ulnar arteries, it is good in the interosseous artery even accompanied by early filling of the deep veins--as seen on the flow of contrast material during angiography. This different behaviour of these three arteries makes a central nervous disorder an unlikely etiology, supported by the fact that drug therapy acting on the central nervous system are only of temporary help. The behaviour of the interosseous artery is easily diagnosed and presents an important clue for functional disturbance of blood flow in the radial and ulnar arteries. The findings were the same, regardless of the type of contrast material used (ionic, non-ionic or dimeric). X