a remnant of the proximal part of the yolk stalk within the embryo that arises as a fingerlike diverticulum, 3-6 cm long, from the antimesenteric border of the ileum between 40 and 50 cm from the ileocecal junction; it may be attached to the umbilicus. If its mucosa includes gastric tissue, peptic ulceration and bleeding may result. SYN: Meckel diverticulum.
