A hernia is the protrusion of an organ or tissue out of the body
cavity in which it normally lies. By far the most common hernias
develop in the abdomen, when a weakness in the abdominal wall
evolves into a localized hole, or "defect", through which the
protrusion occurs. These may present either with pain at the site,
a visible or palpable lump, or in some cases by more vague symptoms
resulting from pressure on an intraabdominal organ which has become
"stuck" in the hernia. Fatty tissue usually enters a hernia first,
but it may be followed by or accompanied by a segment of intestine
or other intraabdominal organ. It is generally advisable to repair
hernias in a timely fashion, in order to prevent complications
which include intestinal blockage, gangrene, and death. Most
hernias can be surgically repaired. Recovery rarely requires
long-term changes in lifestyle.
By far the most common abdominal hernias are the so-called inguinal
hernias. Named for the Latin word for "groin", these involve the
bulging of abdominal contents into a defect in the inguinal canal
in the lower abdomen. Since they involve the embryological route of
descent of the testicle, inguinal hernias are more common in males
than females, and in males the hernia contents commonly enter the
scrotum. Inguinal hernias are further divided into the more common
"indirect inguinal hernia", in which the inguinal canal is entered
via a congenital weakness at its apex, and the "direct" type, where
the hernia contents push through a weak spot in its back
wall.
Other abdominal hernias include umbilical, femoral, incisional, and
diaphragmatic. Umbilical hernias, especially common in infants of
African descent, involve protrusion of intraabdominal contents
through a weakness at the site of passage of the umbilical cord
through the abdominal wall. While these often resolve spontaneously
in children, in some communities mothers routinely push the small
bulge back in and tape a coin over the palpable hernia hole until
closure occurs. This practice is not medically recommended as there
is a small risk of trapping a loop of bowel under part of the coin
resulting in a small area of ischaemic bowel.
Femoral hernias, which can be virtually indistinguishable from the
inguinal type, occur just below the groin crease, when abdominal
contents pass into the weak area created by the passage of the
femoral blood vessels into the lower extremities. An "incisional
hernia" occurs when the defect is the result of an incompletely
healed surgical wound. Higher in the abdomen, an (internal)
"diaphragmatic hernia" results when part of the stomach or
intestine protrudes into the chest cavity through a defect in the
diaphragm. A hiatus hernia is a particular variant of the latter in
which the normal passageway through which the esophagus meets the
stomach serves as a functional "defect", allowing part of the
stomach to periodically "herniate" into the chest.
(From Wiki-Pedia.com)
