Main Model
Rectum
The large intestine is where water is absorbed from the indigestible residues of the liquid chyme, converting it into semisolid stool or feces that is stored temporarily and allowed to accumulate until defecation occurs. The large intestine consists of the cecum; appendix; ascending, transverse, descending, and sigmoid colon; rectum; and anal canal.
The rectum is the fixed (primarily retroperitoneal and subperitoneal) terminal part of the large intestine. It is continuous with the sigmoid colon at the level of S3 vertebra. The junction is at the inferior end of the mesentery of the sigmoid colon. The rectum is continuous inferiorly with the anal canal.