[Aneurysms. A rare cause of ulnar nerve compression in the palm].

A case of an aneurysmatic dilatation of the ulnar artery with compression of the ulnar nerve in Guyon's canal is described. The etiology, symptomatology, and therapy are illustrated. Acute or chronic trauma in the hypothenar eminence caused pain not only here but also in the ulnar side of the hand with paraesthesia in the ulnar region. It was due to compression of the ulnar nerve in the loge de Guyon by a largely dilated and thrombosed arterial aneurysm. The diagnosis was confirmed by angiogram of the arm and hand. Resection and reconstruction was advised and showed good results.