McBurney point.
Summary
McBurney point is the surface landmark for the base of the appendix, located one-third of the way from the right anterior superior iliac spine to the umbilicus. Tenderness here is the classic sign of acute appendicitis.
Detail
Charles McBurney described the point in 1889 as the site of maximal tenderness in appendicitis and it remains the standard landmark for both examination and the oblique gridiron incision used in open appendicectomy. Pain in appendicitis migrates from the periumbilical region, where it is referred visceral pain at the T10 dermatome, to McBurney point once the parietal peritoneum becomes inflamed. Anatomical variation is important: the appendix may be retrocaecal in about two-thirds of people, in which case tenderness is less marked and the psoas sign more useful, or pelvic, producing suprapubic pain, diarrhoea, and tenderness on rectal examination. In pregnancy the appendix is displaced upward by the gravid uterus, so pain may localize to the right upper quadrant. Progression to perforation typically occurs after twenty-four to seventy-two hours and converts localized tenderness into generalized peritonitis.
Sources
- Schwartz's Principles of Surgery
- Gray's Anatomy for Students
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