<prompt> What is the following most characteristic feature of congenital hyperophic pyloric stenosis?The patient is commonly marasmicIt is associated with early loss of appetiteIt mostly affects the first born female childThe pyloric tumour is best felt during feeding  <response>: Diagnosis of congenital hyperophic pyloric stenosis can be made with a test feed, which produces a characteristic peristaltic wave which is seen to pass across the upper abdomen. Palpation of the abdomen at that time reveals the lump. Ref: Bailey and Loves Sho Practice of Surgery, 24th Edition, Page 1033. 