Unusual presentation of ulnar artery aneurysm and dissection with associated anomalous radial artery: appearances on multi-detector row CT angiography.

We present a case of ulnar artery aneurysm and dissection associated with a congenitally hypoplastic ipsilateral radial artery. We postulate that the aetiology is due to increased blood flow through the ulnar artery as a consequence of the radial artery anomaly, therefore making the ulnar artery more vulnerable to aneurysm formation and traumatic damage. This might represent a variant of the hypothenar hammer syndrome with associated ulnar artery dissection and recurrent distal embolisation manifesting as Raynaud's phenomenon. Forearm arterial injuries, treatment and the importance of upper limb arterial anatomical variations are also discussed. To our knowledge, this is the first reported case of its type diagnosed by multi-detector row computed tomography angiography.