Malrotation and volvulus

Abstract

The term malrotation is used to denote the situation where the embryonic bowel, during the period when it herniates into the coelom of the body stalk between the 4th and 10th week of gestation, fails to rotate correctly. This means that when it returns to the abdominal cavity it is not correctly oriented, preventing the normal process of fixation of the midgut and its mesentery to the posterior abdominal wall. This results in a narrowed "universal" mesentery, which predisposes to volvulus. Volvulus is the term given to abnormal twisting of bowel (which, in the case of malrotation, involves most of the midgut) on its mesentery, and may have the consequence of cutting off its blood supply leading to ischaemia or infarction of the bowel.