Fig. 12
From: The growth pattern of the human intestine and its mesentery
“Rotation” of the midgut relative to the superior mesenteric artery. The diagram shows the changes in position (“rotation”) of the indicated intestinal structures relative to the SMA as seen from ventral. Cranial relative to the SMA represents 0° and the gut “rotates” counterclockwise. The squares represent rotation associated with the primary loop. The diamonds show the degree of rotation between 5.5 and 8.5 weeks, while the circles show the degree of rotation during and immediately after intestinal return (9th week). Only rotation and not distance to the SMA are shown, so that rotation during intestinal return appears extensive, whereas the change in position is only minor. We conclude that the intestines do not “rotate” but “slide” from the umbilical orifice to the lower-right abdominal cavity