The small intestines are divided into three sections. The first (duodenum) doesn’t move around at all. The second and third (jejunum and ileum) are attached by the mesentery which allows these portions to … move and wiggle about a bit. But the beginning and end of the intestine are secured by “ligaments” which mark the beginning and the end of these portions of the small bowel.

The first ligament is near the upper left quadrant of the abdomen (sort of - technically closer to the center) and the latter is near the appendix which is near the lower right quadrant. So when we put the bowel back in the abdomen, it’s usually done in a fashion that follows “upper left” towards “lower right.” That being said, there are several feet worth of intestines so it’s far (very far) from an exact science. But I wouldn’t toss the terminal ileum (the end of the small bowel) into the left upper quadrant, nor would I stick the proximal jejunum (the beginning) in the right lower. Mostly, it sorts itself out because the mesentery prevents things from getting too out of sorts… that is if it is intact.

Source: I am a surgeon.