[Hypothenar hammer syndrome is rare - or simply an unusually overlooked condition].

Hypothenar hammer syndrome is a possibly underdiagnosed but treatable cause of Raynaud's phenomenon and hand ischemia elicited by thombosis or aneurysm secondary to acute or chronic blunt trauma to the ulnar artery at the level of Guyon's canal. This paper provides a summary of the condition with some emphasis on prophylactic and therapeutic aspects.