Ro·ger \rȯ-zhā\ Henri–Louis (1809–1891), French physician. Roger made his principal contribution in pediatrics and was the first to give systematic clinical instruction in this field. His early research centered on auscultation, a subject on which he wrote a monograph. In 1879 he described an abnormal congenital opening between the ventricles of the heart; this congenital defect is now known as the maladie de Roger. He was not the first to describe this defect, but he was the first to make clinicopathologic observations based on a number of cases.