Rectal Swelling Anatomy
To better understand proctitis, it helps to understand the anatomy of the colon, rectum and anus.
The large intestine is also known as the colon. It is the last portion of the intestine.
The colon has several parts, including:
- The portion of the colon that connects to the ileum (small intestine). The appendix is a finger-like pouch that comes off of the cecum.
- Ascending colon:
- The first section after the small intestine, located on the right side
- Transverse colon:
- Sits horizontally across the upper abdomen
- Descending colon:
- Located on the left side of the abdomen
- A short, S-shaped section above the rectum
- The lowest internal part of the colon
- Babb RR. Radiation proctitis: a review. Am J Gastroenterol. 1996 Jul;91(7):1309-11. 
- Gionchetti P, Rizzello F, Morselli C, Campieri M. Review article: problematic proctitis and distal colitis. Aliment Pharmacol Ther. 2004 Oct;20 Suppl 4:93-6.