[1] The majority extend transversely around the cylinder of the small intestine,[2] for about one-half or two-thirds of its circumference.

In the lower part of the descending portion, below the point where the bile and pancreatic ducts enter the small intestine, they are very large and closely approximated.

[citation needed] Unlike the gastric folds in the stomach, they are permanent, and are not obliterated when the intestine is distended.

The circular folds slow the passage of the partly digested food along the intestines, and afford an increased surface for absorption.

[3] This article incorporates text in the public domain from page 1173 of the 20th edition of Gray's Anatomy (1918)