Anatomy of the appendix

2021-05-12 03:50 PM

The disease can be present at any age, but the highest incidence of the disease occurs in adolescents and young people. Men have a 5 times higher incidence of disease than women.

The human appendix remains a mysterious organ because its function is unknown. It is believed that the appendix has similar immune functions to the bird's Fabricius sac.

The appendix is ​​variable in size, usually 0.5-1cm in diameter, and about 8cm long. The appendix root poured into the cecum about 3cm below the angle of the ileum, where 3 longitudinal muscles converge. The appendix has a mesenteric and is very mobile, and can be located in many locations. Normally the appendix is ​​located at the point between the line connecting the upper anterior pelvic spine to the navel (Mac Burney point).

The wall of the appendix is ​​very thick, has a 4-layer structure like the large intestine. A special feature is that the appendix has a lot of lymphoid tissue in the mucosa and submucosa. In the young, the lymphoid forms a continuous layer with the lymphoid cysts.

Lymphoid tissue shrinks with age and disappears in the elderly (at that time, the distal part of the appendix is ​​also fibrosis).

Acute appendicitis

The disease can be present at any age, but the highest incidence of the disease occurs in adolescents and young people. Men have 5 times higher incidence of disease than women.

Half a century ago, Wangenstean et al. Demonstrated that appendix congestion leads to inflammation. The appendix can become clogged with hard, lumpy, lumpy stools, a cluster of parasites (pinworms). Rarely, the appendix becomes blocked by an external cord, due to hyperplasia of the lymphoid tissue in the lumen (associated with systemic viral infection).

When the appendix is ​​blocked, along with mucus secreted, the pressure in the lumen of the blocked intestine increases, causing the veins to collapse. Anaemia is then followed by an opportunity for bacteria to invade, causing an inflammatory response to oedema and secretion. Anaemia and bacterial invasion form a vicious cycle that intensifies inflammation.

However, there are also a few cases where the appendix is ​​not obstructed and still has acute inflammation, in which cases the cause is unknown.

At first, there was only a small amount of effusion containing polymorphonuclear leukocytes in the mucosa, submucosa (sometimes with mucosal lesions) and accompanied by congestion and leukocyte infiltration below the serosa.        

At that time, the serosa is smooth, shiny, firm and speckled with seeds (acute appendicitis in early-stage).

Later, polymorphonuclear leukocytes penetrate more layers of the intestinal wall, especially in the muscle layer. The serosa is covered with pus fibrin. Subsequently, there are abscesses in the wall with ulcers and purulent necrosis in the mucosa (acute purulent appendicitis).

If it gets worse, there are mucosal haemorrhagic ulcers, necrosis and gangrene in the wall that reaches the serosa, which can cause appendiceal rupture (acute necrotizing appendicitis), peritonitis, or appendiceal abscess. 

Very rare cases can cause complications of purulent phlebitis, liver abscess.

The progression of acute appendicitis is very rare, and it is possible to self-repair and scar if there is little damage. Sometimes it turns to chronic inflammation with a fistula.

The appendix can also be affected by other conditions such as Crohn's disease, typhoid fever, and amoebic enteritis.

Chronic appendicitis

Very rarely, most often, repeated acute attacks that make people think of chronic appendicitis.

In some patients, the appendix is ​​just a fibrous tissue from birth and is considered the result of a chronic inflammatory response.