A hernia is nothing but a protrusion of any organ of the body out of the cavity that usually contains it and pushes through to another part of the body.
The most common kinds of hernia are those of the abdomen, followed by those of the spinal discs and sciatica.
There are different kinds of hernia, which have different causes and indications:
Inguinal Hernia: This is the commonest kind of hernia (an estimated 70% of abdominal hernias may be of this type).
Usually this kind of hernia happens when a portion of the intestine protrudes through the abdominal wall. This could be because of muscle weakness or a tear. This forms a noticeable and painful out-pouching.
Sometimes, the cause is congenital, in which case the hernia could occur in babyhood. Other causes include old age, obesity or pregnancy.
Inguinal hernias can also occur due to strenuous activities such as heavy lifting, or due to chronic conditions such as constipation, repeated episodes of sneezing and coughing (as observed in the case of smokers). Obesity also could cause this kind of hernia.
Hiatal Hernia: This kind of hernia involves the diaphragm, the stomach and the chest cavity. Here, the stomach pushes up and into the chest cavity through the opening in the diaphragm.
While the underlying causes are not fully understood, these hernias are thought to be caused due to an injury in the area or perhaps a congenital defect that created a larger than normal hiatal opening or weak or defective muscles in the area.
Extreme pressure on the abdomen could also cause this kind of herniation as also other activities that create pressure such as heavy lifting, constipation, chronic vomiting or coughing. Pregnancy could also be a cause.
Incisional Hernia: This kind of hernia occurs when there is a surgical wound that has not healed properly. These hernias are usually very difficult to treat.
Umbilical Hernia: This kind of hernia occurs due to a weak area of the wall of the abdomen which causes the umbilical cord to protrude.
Usually this kind of hernia is seen in babies; however adults can have it too and is usually caused by a congenital defect.
Other causes include extra fluid in the abdominal area, obesity, multiple pregnancies and other pressure such as lifting, coughing etc.