Midgut Malrotation

Excerpt

Midgut malrotation is a developmental rotational anomaly of the embryonic bowel. Malrotation can present as either acutely, intermittently, or asymptotically. The diagnosis of malrotation with subsequent volvulus of the intestine represents acute surgical emergencies.

During embryonic development, the small bowel usually rotates in a counterclockwise direction around the superior mesenteric artery (SMA) axis between the fourth to eight weeks of gestation. During this period in embryonic development, the bowel protrudes through the yolk stalk (which will become the future umbilicus). During this process, the digestive tract elongates and undergoes counterclockwise 90 degrees rotation, followed by retraction of the bowel into the abdominal cavity where another 180-degrees counterclockwise rotation occurs.

There are different types of Midgut Malrotation:

1. Non-rotation

2. Incomplete rotation

3. Reverse rotation

4. Anomalous fixation of the mesentery