Comprehension: Stomach and Small Bowel
Swallowed barium contrast outlines the position of the stomach, duodenum, jejunum, and ileum in relation to abdominal quadrants. Note the stomach is largely in the left upper quadrant, the duodenum is in the right upper quadrant, the jejunum is in the left upper and left lower quadrants, and the ileum is mostly in the right lower quadrant. The position of the umbilicus is shown in relation to the transcristal line (line across the iliac crests) and the midline. This intersection is usually at the level of L4. A barium enema (below) with reflux of barium into the ileum is shown, and the quadrants are again indicated. The cecum is in the right lower quadrant; hepatic flexure in the right upper quadrant; splenic flexure in the left upper quadrant; and the descending colon is in the left upper and left lower quadrants. The sigmoid colon usually lies in the left lower quadrant and the rectum in the midline. The appendix is not seen in this study, but it is almost always in the right lower quadrant.
Barium Enema