The anal canal is the last stop for poop before it sees the light of day. It's situated between the rectum and anus.
When someone decides it's time (or the body decides for them), poop leaves the rectum, passes through the anal canal, and exits the body through the anus.
Anatomy of the Anal CanalThe anal canal is 2.5 - 4 centimeters long, depending on the person. Its upper half is comprised of anal columns, vertical folds of tissue. Its lower half is comprised of anal valves, folds of tissue that connect the bottoms of the anal columns together. The pectinate line runs underneath the anal valves.
To learn more about colorectal anatomy, please take a look at the Anatomy of the Large Intestine gallery.
- Goldberg, Stephen. Clinical Anatomy Made Ridiculously Simple. MedMaster, 1999.
- Kapit, W. and Elson, L. The Anatomy Coloring Book. Harper Collins, 1977.
- Gross Anatomy: Rectum and Anal Canal, Blood Supply of the Pelvis and Perineum. University of Arkansas for Medical Sciences, Department of Neurobiology and Developmental Sciences. 11 Sep. 2006 [http://anatomy.uams.edu/anatomyhtml/rectumanal.html].
- The Large Intestine. Gray's Anatomy. 11 Sep. 2006 [http://www.bartleby.com/107/249.html].