The term ''lacune'' was coined in 1838 by Dechambre to define small cavities due to the resorption of small infarcts. In 1901, Pierre Marie distinguished lacunes from ''état criblé'' and from single dilatations of the perivascular space around the lenticulo-striate arteries. He defined their volume, number, location and time of occurrence. Unfortunately, there were confusions on the nature of lacunes (infarction, hemorrhage and ''vaginalite destructive''). Sixty-four years later, Fisher considered lacunes as small deep infarcts associated with hypertension and yielding peculiar syndromes. Then, he described arteriolar lesions and emphasized lipohyalinosis. To avoid semantic confusion, a new neuropathological classification has recently been proposed by Poirier. This classification considers as a lacune every void in the brain, less than 20 mm in diameter, whatever the cause of it. This classification included different pathological entities, and there is still an active debate on the origin of lacunes.