2. • A hernia is an abnormal protrusion of a part
or whole of viscus through an abnormal
opening in the wall of the cavity which
contains it In this chapter we are only
concerned with the external abdominal
hernia.
• An external abdominal hernia is protrusion of
abdominal viscus through a weak spot in the
abdominal wall.
3. • The common external herniae are:
1. Inguinal — about 73%;
2. Femoral — about 17%;
3. Umbilical — about 8.5%;
4. Incisional — its incidence is not included.
4. • Other 1.5% cases are rare herniae e.g.
(i) Epigastric;
(ii) Lumbar;
(iii) Spigelian;
(iv) Obturator;
(v) Gluteal.
5. • AETIOLOGY
• Mainly 2 factors play in causing a hernia :—
1. Weakness of the abdominal muscles and
2. Increased abdominal pressure which forces
the content out through the normal
abdominal musculature.
1. Weakness of the abdominal musculature can
be either
• (a) congenital or
• (b) acquired.
6. (a) CONGENITAL WEAKNESS:-
(i) Persistence of processus vaginalis — this
causes indirect complete inguinal hernia.
It is a sort of preformed sac through which
the contents herniate.
• (ii) Similarly patent canal of Nuck in female
causes indirect inguinal hernia.
• (iii) Incomplete obliteration of umbilicus may
lead to infantile umbilical hernia.
7. (b) ACQUIRED WEAKNESS —
(i) Excessive fat in the abdomen causes weakness of the
abdominal musculature.
• Fat separates muscle fibres and thus causes weakness.
• This causes the appearance of direct inguinal hernia,
paraumbilical hemia or hiatus hernia.
(ii) Muscle weakness may follow repeated pregnancy.
(iii) Surgical incisions may lead to division of nerve fibres and
thus causes muscle weakness.
• Example of this is that a direct hernia may develop
following appendicectomy due to division of ilio-inguinal
nerve.
(iv) Incisional hemia develops through weakened abdominal
muscle following a previous operation.
• Mostly infection in the early postoperative period or
excessive fat in the abdominal wall predisposes incisional
hernia.
8. 2. Increased abdominal pressure e.g.
• (i) Whooping cough in children.
• (ii) Chronic cough in bronchitis, tuberculosis etc.
• (iii) Bladder neck obstruction or urethral
stricture.
• (iv) Enlarged prostate causing dysuria.
• (v) Powerful muscular effort or straining during
lifting heavy weight.
• (vi) Vomiting.
• (vii) Repeated pregnancy.
• (viii) Constipation.
9. PATHOLOGY
• A hernia consists of 3 parts —
• (i) the sac,
• (ii) the contents of the sac and
• (iii) the coverings of the sac.
10. • (i) The sac is a pouch of peritoneum which comes out
through the abdominal musculature.
• This sac contains abdominal viscus and it has
coverings starting from the skin to the sac itself. This
sac can be divided into four parts—
• (a) the mouth i.e. the opening of the sac through
which the contents enter the sac,
• (b) the neck of the sac, which is the most constricted
part and it is this part which passes through the
abdominal musculature,
• (c) the body, which is the main portion of the sac and
• (d) thefundus which is the most redundant part of the
sac.
• In children the sac is quite delicate, whereas in adults
in longstanding cases the sac is comparatively thick.
11. • (ii) The contents.—
• The viscus which lies within the sac of a hemia is called the
content of a hernia.
• Depending on the content, the hernia is variously named e.g.
• (a) When the content is omentum, the hernia is called an
omentocele or epiplocele.
• (b) When the content is a loop of intestine, the hemia is called
enterocele.
• (c) When the content is a portion of the circumference of the
intestine, it is called Richter's hernia.
• (d) A portion of the bladder is sometimes present in a direct
inguinal or sliding inguinal or a femoral hernia.
• (e) Ovary may be the content with or without the fallopian tube.
• (f) When the content is Meckel's diverticulum, it is called Littre's
hernia.
• (g) When two loops of small intestine remain in the manner of
‘W it is known as Maydl’s hemia.
• (h) Fluid—slight fluid is almost always present, but it is more when
it is associated with ascites.
• Such fluid may be blood-stained when the hernia is strangulated.
12. • (iii) Coverings are the layers of the abdominal
wall which cover the hernial sac.
• This includes the skin and muscles of the
abdomen.
13. CLASSIFICATION.
• A hernia, irrespective of its site may be either —
• (i) Reducible or
• (ii) Irreducible,
• (iii) Obstructed or incarcerated or
• (iv) Strangulated or
• (v) Inflamed.
14. • Reducible hernia.
• When a hernia reduces itself as the patient lies down
or can be reduced by the patient or by the surgeon, it is
called a reducible hernia.
• One of the 2 most characteristic features of the hernia
is its reducibility.
• The second characteristic feature is impulse on
coughing.
• When the hernia is an enterocele i.e. The content is
small intestine, it gurgles on reduction and the first
portion is difficult to reduce.
• Once reduction is commenced it is easily reduced
particularly the last portion.
• In case of omentocele the first portion is easy to reduce
but it is difficult to reduce the last portion.
• An uncomplicated hernia is usually a reducible hernia.
15. • Irreducible hernia.—
When the contents of the hernia cannot be returned back to the
abdomen it is called an irreducible hernia.
There are various causes of irreducibility :—
• (i) Adhesion of its contents to each other;
• (ii) Adhesion of its contents with the sac;
• (iii) Adhesion of one part of the sac to the other part;
• (iv) Sliding hernia;
• (v) Narrowing of the neck of the sac due to fibrosis following
continued use of the truss;
• (vi) Presence of omentum in the sac often causes irreducibility;
• (vii) When the content is the large intestine which becomes
obstructed (incarcerated);
• (viii) When there is massive hernia inside the scrotum (scrotal
abdomenJ it often becomes irreducible.
• Femoral and umbilical herniae are often irreducible.
• Irreducible hernia is dangerous and may lead to strangulation.
16. Obstructed or Incarcerated hernia
• It is irreducibility plus intestinal obstruction.
• An obstructed hernia means that the hernia
is associated with intestinal obstruction due
to occlusion of the lumen of the bowel.
• The term ‘incarcerated hernia’ is often used
as an alternative to obstructed hernia, but to
be more precise it indicates that a portion of
colon is the content of the sac and is blocked
with faeces.
17. The features of obstructed hernia are
• (i) Expansile coughing impulse is not present;
• (ii) The hemia is irreducible;
• (iii) Patient does not complain of pain;
• (iv) The hemia is lax and not tender,
• (v) Features of intestinal obstruction.
18. Strangulated hernia
• Strangulated hernia (irreducibility + obstruction + arrest of
blood supply to the contents).—
• A hernia is said to be strangulated when the blood supply
of its contents is seriously impaired.
• Ultimately the content becomes gangrenous.
• This condition develops when the neck of the sac is very
much constricted.
• When the intestine is the content, intestinal obstruction
obviously takes place, but intestinal obstruction may not
be present in case of omentocele, Richter’s hernia and
Littre’s hernia.
• Although inguinal hernia is 4 times more common than
femoral hernia, yet a femoral hernia is more likely to
strangulate as the femoral ring is quite tough in
comparison to the superficial inguinal ring.
19. PATHOLOGY
• When the mouth of the sac is very much constricted,
intestinal obstruction first ensues and the intestine within
the sac starts dilating.
• In case of enterocele the venous return is first impeded.
• The intestine becomes congested and bright red.
• Serous fluid is seen oozing out into the sac.
• As venous stasis increases, the arterial supply is also
impaired.
• Ecchymoses appear in the serosa.
• Blood comes out into the lumen of the intestine as also
into the fluid of the sac, so the fluid in the sac becomes
blood stained.
• The serous layer loses its shining character and gradually
becomes dull and covered with fibrinous exudate.
20. • Gradually the intestine loses its tone and it feels flabby.
• The vitality of the intestine diminishes and this favours
migration of bacteria through the intestinal wall and the
fluid within the sac becomes full of bacteria and toxins.
• The mesentery within the sac becomes congested and
haemorrhagic.
• Thrombosis of its vessels occurs.
• Gangrene first appears at the place of constriction and at
the antimesenteric border of the intestine.
• In the places of gangrene the colour changes from purple
to black and ultimately to green.
• Gangrene may start as early as 5 to 6 hours after the onset
of first symptom of strangulation.
• Internal strangulation is more dangerous since spreading
peritonitis sets in from the sac.
21. CLINICAL FEATURES
• Patient first complains of pain and vomiting.
Pain is particularly located at the hernial site.
• In case of internal strangulation it is located at
the umbilicus.
• Soon pain spreads all over the abdomen and
vomiting becomes forcible and frequent.
• If the strangulation is not relieved the paroxysm
of pain continues.
• Such pain will only cease with the onset of
gangrene and paralytic ileus.
• So in case of strangulated hernia spontaneous
cessation of pain is an ominous symptom.
22. • On examination patient is seriously ill. The
hemia is tense and tender.
• Obviously the hernia is irreducible and there
is no impulse on coughing.
• There are also features of acute intestinal
obstruction in case of enterocele.
