What Is the Sigmoid Colon?

The sigmoid colon is part of the large intestine -- the last stretch digested food travels before reaching the colon to be excreted as feces.

The sigmoid colon is the last section of the large intestine that connects the descending colon to the rectum.

It is so-named because it is curved like the letter “S,” which in Greek is sigma (σ). 

The sigmoid colon measures about 14 to 16 inches (35 to 40 centimeters) in length and it forms a loop. It is a hollow tube that measures about 16 inches (40 cm) long and is 2-2/4 inches (7 cm) in diameter.

How Does the Sigmoid Colon Work?

The function of the sigmoid colon is to store fecal waste until it is ready to leave the body through the rectum and anus. Feces is stored in the sigmoid colon for seven hours or more and it is usually expelled from the body when new waste material enters the area.