[Traumatic thrombosis of the distal ulnar artery (hypothenar hammer syndrome) in a golf player with an accessory muscle loop around Guyon's canal. Case report].

Arteriography of a 34-year-old golf player with M. Raynaud symptoms of his left hand revealed filling defects in the digital arteries II to IV fingers associated with corkscrew-like configuration of the ulnar artery in Guyon's space. The preoperative workup including 50 clinical laboratory tests searching for connective tissue diseases, vasculitis, and haematological disorders was without pathological findings; more central embolic sources were excluded angio- and cardiologically. MRI-scan demonstrated an anomalous muscle at the level of the hamate hook located underneath the M. palmaris brevis forming a sling around the ulnar artery. Surgery showed the ulnar artery distal to the anomalous muscle dilated with fibrotic thickening and intraluminal thrombosis. The involved A. ulnaris segment was resected and an interpositional vein graft performed. Histopathologic sections showed fibrosis of the arterial wall with intraluminal thrombosis and elastica fragmentation indicating traumatic genesis (hypothenar-hammer syndrome). We suspect intensive golf playing with the grip style and repetitive movements leading to pressure injury of the hypothenar area and the underlying ulnar artery. Contraction of the anomalous muscle belly may have additionally compressed the artery slowing down the arterial flow and accelerating the thrombosis.