Appendix (anatomy)

Appendix locations

Appendix function diagram

Appendiceal carcinoid 1

Ultrasonography of a normal appendix, annotated

Blausen 0043 Appendix Child

Stomach colon rectum diagram-en

Vestigial organ in the human body

Anatomy

The appendix (or vermiform appendix) is a narrow, tube-shaped pouch attached to the cecum, which is part of the large intestine. It is located in the lower right abdomen. The appendix is considered a vestigial organ, meaning it has lost much of its original function through the course of evolution.

Anatomy

The appendix is typically about 9 cm in length, but it can vary from 2 to 20 cm. It is connected to the cecum, which is the first part of the large intestine, near the junction of the small and large intestines. The appendix has a small mesentery called the mesoappendix, which contains the appendicular artery and appendicular vein.

Function

Historically, the appendix was thought to have no significant function in humans. However, recent studies suggest that it may play a role in the immune system, particularly in the development of gut-associated lymphoid tissue (GALT). It is also hypothesized to serve as a reservoir for beneficial gut bacteria.

Clinical significance

Appendicitis

Appendicitis is the inflammation of the appendix and is a common medical emergency. Symptoms typically include abdominal pain, particularly in the lower right quadrant, nausea, vomiting, and fever. If untreated, an inflamed appendix can rupture, leading to peritonitis, a serious infection of the abdominal cavity.

Surgical removal

The surgical removal of the appendix is known as an appendectomy. This procedure is commonly performed to treat appendicitis. Appendectomies can be performed using traditional open surgery or laparoscopic surgery, which is less invasive and typically has a quicker recovery time.

Evolutionary perspective

The appendix is considered a vestigial structure, meaning it has lost much of its original function over time. In some herbivorous animals, the appendix is larger and plays a role in the digestion of cellulose. In humans, the appendix is much smaller and its function is not as critical.

Related pages

• Digestive system
• Large intestine
• Cecum
• Appendicitis
• Appendectomy
• Peritonitis