(mek'ĕl )

Ger. anatomist, 1781–1833, grand son of J.F. Meckel, the elder.

M. cartilage A cartilaginous bar about which the mand ible develops.

M. diverticulum A congenital sac or blind pouch found in the lower portion of the ileum. It represents the persistent proximal end of the yolk stalk. Sometimes it is continued to the umbilicus as a cord or as a tube forming a fistulous opening at the umbilicus. The diverticulum may become a focal point for intestinal obstruction progressing to strangulation; become inflamed with symptoms mimicking acute appendicitis; and as a result of the variable presence of gastric mucosa, may develop peptic ulcer symptoms, including hemorrhage. Surgery is necessary for any of these clinical presentations.

SEE: diverticulitis.

M. plane A plane through the auricular and alveolar points.

M. scan A radionuclide scan to demonstrate the presence of a Meckel diverticulum. The diverticulum may be difficult to visualize with plain films, barium studies, colonoscopy, or computed tomography imaging.