Plénies sign is one of the main symptoms of peritoneal irritation reported in the Czech medical literature and used in clinical practice. However, it is not known who Plénies really was. The author reveals his identity with the help of archival materials, registers and contemporary press, presents a key article and lecture in which this symptom is described, and provides a basic biography and bibliography of this forgotten physician.
Keywords: Plénies sign; acute abdomen; peritoneal irritation.