Appendicitis is a commonly known problem among the public. It is a basically an inflammatory process involving a clinically important part of the gastro intestinal tract- the appendix.
Anatomy of appendix
The vermiform appendix is a blind ended tube which arises from the posteromedial aspect of the ceacum. It is nearly 2 - 2.5cm below the ileoceacal valve and can grow up to 1.5- 22cm in length.
The base of the appendix is at the point where all 3 taeniae coli of the ascending colon converge. This feature is used in tracking and pointing the appendix during a surgery. Although the base is almost always at this constant position, the remaining tube can lie in highly variable positions. Most common one is the retrocaecal position followed by the retro colic position. It can also be found in subcaecal, pre-ileal and retro ileal positions.
Note :- that a very long appendix can even ulcerate into the duodenum or left para colic gutter.
This organ has its own mesentry, the mesoappendix. The appendicular artery from the ileocolic branch of the superior mesentric artery runs in between the layers of meso appendix. This supplies the appendix. The ileocaecal fold is a peritoneal fold running from the front of ileum to the base of appendix or to the caecum. It is also known as the avascular fold of Treves.
Inside the tube the wall layers consists of densely packed lymphoid tissues. But the exact function or importance of the organ remains uncertain.
This is the inflammatory reaction in the vermiform appendix. If it persists and bursts out into the peritoneal cavity it causes peritoneal abscess and consequent pain. The exact cause is not constant and less clear. But the obliteration of the tube in adults may lead to the inflammation.
Initially the pain is felt at the periumbilical region. (The abdominal area surrounding the umbilicus) This is the referred pain of the viscera.
But at the late stages, the pain is felt heavily at the right iliac fossa region. (The right lower quadrant) This is because of the irritation to the peritoneal layer by the swollen appendix or by the abscess.
It may also irritate the posas major muscle, making the light lower limb a little flexed. If the limb is extended pain will be increased. This is confirmed by a psoas test.
Usual treatment is appendectomy, the total removal of appendix. Carried out by a muscle spiltting incision in the abdomen which is known as the Mc.burney's insicion or the grid iron incision. The Mc.burneys point is a surface marking for the base of appendix. It is marked at the junction between lateral 1/3 and medial 2/3 of a line joining the right ASIS (anterior superior iliac spine) and the umbilicus. But this incision causes heavy scarring. So a transitional inscion along the tension lines is also used for the procedure in patients who prefer cosmetic aspects.
But these days, the appendectomy is commonly carried out laparoscopycally. It is the easiest way with minimal scarring.