Bowel malrotation; Malrotation of the gut
Intestinal malrotation (ΙΜ) is a congenital anomaly characterized by a disturbed topography within the abdominal cavity, involving primarily the duodenojejunal and ileocolic loops. It includes abnormalities of both rotation and fixation of the intestinal tube and, generally, results from the disordered embryonic counterclockwise rotation of the gut around the superior mesenteric artery (SMA) leading to a more or less unanchored bowel, a narrow base mesentery, and various acute and chronic presentations of disease.
The basic intestinal movement inside the abdomen of the developing embryo consists of a two- to three-stage anticlockwise rotation of the two segments of the initially symmetrically suspended midgut, meaning the more rapidly elongating cranial (prearterial) limb and the more slowly elongating caudal limb (postarterial) around the axis of the SMA. The first stage, beginning at the 5–6 weeks, consists of a 90° twist...