Eponym
The sign is named for American surgeon Charles McBurney, (1845–1913).
In fact, McBurney himself did not locate "his" point in such a precise way in his original article.
The seat of greatest pain, determined by the pressure of one finger, has been very exactly between an inch and a half and two inches from the anterior spinous process of the ilium on a straight line drawn from that process to the umbilicus —Charles McBurney, "Experience with Early Operative Interference in Cases of Disease of the Vermiform Appendix"; New York Medical Journal, 1889, 50: 676-684 .Read more about this topic: McBurney's Point