Intestinal Malrotation and Midgut Volvulus

The danger is not simply that the intestine is in an unusual position. During embryonic development, the midgut normally rotates 270 degrees counter-clockwise around the superior mesenteric artery (SMA). When that rotation is incomplete, the bowel is left with a short, narrow mesenteric attachment rather than a broad, stable base. A narrow base makes twisting possible. A useful anatomical picture is a long, mobile loop suspended from a narrow hinge: the loop can turn around the SMA. That twist is a midgut volvulus. It obstructs the bowel and may compress the mesenteric vessels at the same time. Obstruction produces vomiting and distension; impaired blood flow produces ischemia, necrosis, perforation, peritonitis, and shock. The combination of malrotation and volvulus is therefore a time-critical abdominal emergency, particularly in a neonate or infant. The bowel can lose perfusion before dramatic abdominal findings appear. A practical nurse should treat the pattern of green vomiting plus clinical deterioration as more urgent than the degree of distension alone.