Abdominal herniae

Question 1

What is a hernia?

Answer 1

A protrusion of an organ or part of an organ through a defect in the wall of the cavity containing it, into an abnormal position.

Question 2

What is the aetiology of hernia?

Answer 2

Occur at sites of weakness in abdo wall e.g congenital (e.g. persistence of processus vaginalis of testicular descent –> congenital inguinal hernia), site of penetration of structures (e.g. femoral canal), surgical incision.

Question 3

What are the varieties of hernia?

Answer 3

Reducible, irreducible, strangulated.

Question 4

What is a reducible hernia?

Answer 4

The contents of the hernia can be replaced completely into the abdominal cavity.

Question 5

What is an irreducible hernia?

Answer 5

Hernia usually becomes irreducible due to

i) adhesions of its contents to the inner wall of the sac, or
ii) adhesions of contents to each other to form mass greater in size than neck of sac.

Question 6

What is a strangulated hernia?

Answer 6

Contents of the hernia constricted by neck of the sac so circulation is cut off.
Unless relieved, gangrene inevitable –> perforation of gangrenous loop.

Question 7

What are the clinical features of a reducible hernia?

Answer 7

Lump that may disappear on lying down. Usually not painful.

Examination: reducible lump with cough impulse.

Question 8

What are the clinical features of an irreducible hernia?

Answer 8

Hernia that will not reduce but is painless, with no other symptoms.
Absence of cough impulse does not imply strangulation.

Question 9

What are the clinical features of a strangulated hernia?

Answer 9

Sudden onset, severe pain in the hernia; + colicky central abdominal pain.
Other symptoms of intestinal obstruction: vomiting, distension, absolute constipation.
Examination: tender, tense hernia that cannot be reduced and does not have a cough impulse. Overlying skin inflamed and oedematous, noisy bowel sounds.

Question 10

What are the three most common hernia to strangulated?

Answer 10

i) Femoral
ii) Indirect inguinal
iii) Umbilical

Question 11

What are the classifications of inguinal hernia?

Answer 11

i) Indirect: entering the internal inguinal ring and traversing the inguinal canal. If large enough emerges through external ring into scrotum.
ii) Pushing through the posterior wall of the inguinal canal medial to the internal ring.

Question 12

Describe the anatomy of the inguinal canal anteriorly.

Answer 12

Skin, superficial fascia and external oblique aponeurosis covers the full length of the canal.
The internal oblique aponeurosis covers its lateral third.

Question 13

Describe the anatomy of the inguinal canal posteriorly.

Answer 13

The conjoint tendon (representing the fused common aponeurotic insertion of the internal oblique and transversus abdomens muscles into the pubic crest) forms the posterior of the canal medially.
The transversals fascia lies laterally.

Question 14

Describe the anatomy of the inguinal canal superiorly.

Answer 14

The lowest fibres of the internal oblique and transversus abdominis.

Question 15

Describe the anatomy of the inguinal canal inferiorly.

Answer 15

Inguinal ligament.

Question 16

What is the inguinal canal.

Answer 16

Passage in the lower abdominal wall that extends inferiorly and medially. It is superior to the inguinal ligament. It acts as a pathway by which structures can pass from the abdominal wall to the external genitalia.

Question 17

What is the mnemonic for the inguinal ligament?

Answer 17

MALT (2 x MALT)
M: Superior wall (roof): 2 muscles
-Internal oblique and transversus abdominis muscle
A: Anterior wall: 2 aponeuroses
-Aponeurosis of external oblique and internal oblique
L: Lower wall: 2 ligaments
-inguinal ligament
-lacunar ligament
T: posterior wall: 2 Ts
-Transversalis fascia, conjoint tendon.

Question 18

What is the internal inguinal ring?

Answer 18

The point at which the spermatic cord pushes through the transversalis fascia.
Demarcated medially by the inferior epigastric vessels as they pass upwards from the external iliac artery and vein.

Question 19

What is the external inguinal ring?

Answer 19

Inverted V-shaped defect in the external oblique aponeurosis. Lies immediately above and medial to the pubic tubercle.

Question 20

What does the inguinal canal transmit?

Answer 20

The spermatic cord (round ligament in female) and the ilioinguinal nerve.

Question 21

How can an indirect inguinal hernia be controlled if it is reducible?

Answer 21

Pressure with one fingertip over the internal inguinal ring, which lies 1-2cm above the point where the femoral artery passes under the inguinal ligament (i.e. 1-2cm above the femoral pulse)

Question 22

What are the two most important features of an indirect inguinal hernia? Why do they occur?

Answer 22

Due to narrow opening of inguinal ring:

i) Hernia does not reach full size until patient has been up for some time, does not reduce immediately.
ii) Likely to strangulate.

Question 23

Are indirect or direct inguinal hernia more common in infancy and adolescence?

Answer 23

Indirect. May be congenital.

Direct: always acquired.

Question 24

What is a femoral hernia?

Answer 24

Passes through the femoral canal, lying at the medial extremity of the femoral sheath (containing femoral artery and vein).

Question 25

What are the clinical features of a femoral hernia?

Answer 25

Globular swelling below and lateral to the pubic tubercle. Enlarges on standing and coughing, may disappear on lying.

Question 26

Are femoral herniae prone to strangulation? Why?

Answer 26

Yes. Neck of femoral canal is narrow and has sharp medial border. Hence prone to irreducibility and strangulation.