The vermiform appendix, also known simply as the appendix, is an organ in the human body which appears to be vestigial, meaning that it is a remnant of an earlier stage in human evolution, although some doctors have suggested that this organ may actually have a function. Some people are familiar with the vermiform appendix in the form of an organ which becomes infected, causing death if it is not removed in an appendectomy procedure. At one time, surgeons routinely took the appendix out during surgeries for other issues, under the assumption that it could become infected in the future, but this practice is no longer common.
This organ protrudes from the cecum, a pouched area of the colon located on the right side of the body. Normally, the appendix is found in the lower right abdomen. When it becomes infected, it creates a characteristic dull pain, with appendicitis usually being diagnosed when a doctor palpates the lower abdomen. The “vermiform” is a reference to the fact that the appendix resembles a little worm dangling from the cecum.
In addition to becoming infected, the appendix can also sometimes become cancerous. Removal of the appendix appears to have no ill affect on patients, leading doctors to surmise that this organ has no function. Some people have suggested that the vermiform appendix may have once been larger, and used to help humans digest leaves and other roughage. This theory is supported by the presence of similar organs in animals like koalas, who eat a great deal of roughage routinely.
Inspections of the appendix have revealed that it is unusually high in lymph cells. This discovery has led some doctors to suggest that the vermiform appendix may actually play a role in the immune system. It may serve as a reservoir for immune cells, boosting the immune system when the body is having difficulty fighting off disease and infection. The fact that people don't seem to suffer without an appendix makes it difficult to prove this theory.
Doctors can also use the vermiform appendix in reconstructions of other organs, such as the bladder. This is why the appendix is now left in unless it becomes infected, under the argument that it could be useful as a “spare part” in the event that its host develops a medical problem.
While the vermiform appendix is famous, it is far from the only vestigial body part. Humans have a structure in their skulls called the vomeronasal organ or Jacobson's organ which appears to have no current function, although this organ is used in numerous other mammals. Intriguingly, both the vermiform appendix and vomeronasal organ appear to be active during fetal development, suggesting that these organs may be performing some sort of function while humans are in the womb. Some adolescents also develop wisdom teeth, also known as mandibular third molars, another legacy of earlier humans.