The vermiform appendix is also referred to as the vermix, the cecal appendix, or appendix. It is a tube that connects to the cecum. The cecum is the structure of the colon that resembles a pouch. The location of the appendix is close to the junction of the large intestine and the small intestine.

Although the physiologic function of the appendix is not clearly established, it is thought to be a vestigial remnant (from a primitive version of the large intestine). Most researchers agree that it has a minor role in immune function.

In Latin, the term 'vermiform' means worm-shaped. Although the appendix ranges from a length of two centimeters to twenty centimeters, the average length is ten centimeters. The appendix usually has a diameter between seven and eight millimeters. Historically, the largest appendix that has ever been removed from someone was twenty-six centimeters long and came out of a patient in Zagreb, Croatia.

Most of the time, the vermiform appendix is located on the right side of the abdomen in the lower quadrant. In rare cases, however, it can be located on the lower left side of the abdomen and is indicative of a condition called situs inversus.

Blockage of the appendix can lead to appendicitis, a type of inflammation that is painful and potentially deadly. A blocked appendix can eventually burst, which releases dangerous bacteria into the abdominal cavity. Appendicitis is usually treated with an appendectomy, surgical removal of the appendix.