To better understand appendicitis, it helps to understand the anatomy of the intestines and the appendix.
The intestine absorbs nutrients from food and liquids. The intestine is about 22 feet long in an adult. It includes the large intestine and the small intestine.
The small intestine has three parts:
- Connects to the stomach
- Middle portion of the small intestine
- Lower portion of the small intestine that connects to the cecum (first part of the large intestine)
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
- Alloo J, Gerstle T, Shilyansky J, Ein SH. Appendicitis in children less than 3 years of age. Pediatr Surg Int. 2004 Jan;19(12):777-9. 
- Andersson RE. Meta-analysis of the clinical and laboratory diagnosis of appendicitis. Br J Surg. 2004 Jan;91(1):28-37. 
- Hagendorf BA, Clarke JR, Burd RS. The optimal initial management of children with suspected appendicitis: a decision analysis. J Pediatr Surg. 2004 Jun;39(6):880-5. 
- Shelton T, McKinlay R, Schwartz RW. Acute appendicitis: current diagnosis and treatment. Curr Surg. 2003 Sep-Oct;60(5):502-5.