SUBUNGUAL splinter hemorrhages are generally considered to be part of the clinical picture of bacterial endocarditis, but the fact that they are also seen in a wide variety of other conditions has been appreciated only recently.
The association of splinter hemorrhages with bacterial endocarditis dates to 1920, when Sir Thomas Horder described "a minute petechia in the form of a vivid linear splash of red at the side of the bed of a finger nail" in a patient with bacterial endocarditis.1 In 1923, Blumer in his work on bacterial endocarditis reported "curious subungual linear hemorrhages which look exactly like a splinter under the nail," and for the next three decades the splinter hemorrhage became firmly associated with bacterial endocarditis.2
In 1958, Platts and Greaves 3 pointed out that splinter hemorrhages occurred in many patients who were not suffering from bacterial endocarditis. Subsequently other European investigators confirmed these observations.
KILPATRICK ZM, GREENBERG PA, SANFORD AJP. Splinter Hemorrhages-Their Clinical Significance. Arch Intern Med. 1965;115(6):730-735. doi:10.1001/archinte.1960.03860180102019