Inguinal hernia

Question 1

Define the terms with respect to the description of hernias:

1. reducible
2. irreducible
3. incarcerated
4. obstructed
5. strangulated
6. sliding

Answer 1

1. Reducible:
   
   • The contents of the hernia can be completely replaced into the cavity
2. Irreducible:
   
   • The contents of the hernia cannot be completely replaced into the cavity
3. Incarcerated:
   
   • The contents of the hernia sac are stuck inside by adhesions
4. Obstructed:
   
   • Bowel contents cannot pass through the herniated bowel
5. Strangulated:
   
   • There is ischaemia of the contents of the hernia (due to obstructed venous return), which unless relieved will lead to gangrene and perforation
6. Sliding:
   
   • Sliding hernias are those in which part of the wall of the sac is formed by a viscus.

Question 2

Describe the anatomy of the inguinal canal.

How does it form?

Where is it?

What does it contain?

Answer 2

• The inguinal canal is formed by the relocation of the testes during the foetal development.
• It is about 4cm long and lies parallel and medial to the first part of the inguinal ligament.
• It contains:
  
  • 3 arteries (testicular/ovarian, artery to the vas deferens, cremasteric artery)
  • 3 nerves (genital branch of genitofemoral, ilioinguinal and sympathetic nerves)
  • 3 other structures (the vas deferens/round ligament of the uterus, the pampiniform plexus and testicular lymphatics)

Question 3

Where are the superficial and deep rings of the inguinal canal located?

Answer 3

• The deep inguinal ring is the entrance to the inguinal canal, located 1cm superior to the mid-point of the inguinal ligament (halfway from ASIS to pubic tubercle)
• The superfical inguinal ring is the exit of the inguinal canal, and this is found 1cm superior and lateral to the pubic tubercle

Question 4

Define indirect and direct inguinal hernia

Answer 4

Indirect (also known as congential inguinal hernia):

• Viscus traverses entire length of inguinal canal, entering at the deep ring and leaving at the superficial ring.
• The deep ring is lateral to the inferior epigastric vessels. (make up 2/3rd of inguinal hernias)

Direct (also known as acquired inguinal hernia):

• Viscus breaks through weakness in the transversalis fascia, and passes through the superficial ring.
• The breach is commonly medial to the inferior epigastric vessels. (make up 1/3rd of inguinal hernias)

Question 5

List the factors that predispose to the development of inguinal hernia

Answer 5

• Increased intra-abdominal pressure:
  
  • chronic cough
  • heavy lifting
  • pregnancy
  • obesity,
  • straining at micturition/defecation)
• weakness of transversalis fascia (previous hernia, age) are two big factors influencing development of inguinal hernias.

Question 6

Describe the physical findings in patients with reducible inguinal herniae, including examination of the external ring and descent to the scrotum, and incarcerated inguinal herniae including the signs of bowel obstruction and possible strangulation

Answer 6

Asking the patient to cough, increasing intra-abdominal pressure, will lead to an impulse through the hernia.

• Reducing the hernia may allow for control at the deep inguinal ring if it is an indirect hernia (as it will pass through here).
• Scrotal continuation of a hernia is more common in indirect hernia but may occur in either.
• Incarceration will cause bowel obstruction, characterised by constipation, distension, vomiting, and pain.
• On examination there will be increased bowel sounds.
• Strangulation and ischaemia will be associated with the four signs of inflammation (pain, redness, swelling, warmth) and tenderness.

Question 7

What are the boundaries of the inguinal ligament?

Answer 7

• MALT (2 Muscles, 2 aponeuroses, 2 ligaments, 2 ‘T’s Superior wall
• 2 muscles:
  
  • Internal oblique
  • Transversalis abdominus
• Anterior wall (2 aponeuroses):
  
  • Aponeurosis of external oblique
  • aponeurosis of internal oblique
• Inferior wall (2 ligaments):
  
  • Inguinal ligament
  • lacunar ligament
• Posterior wall (2 T’s):
  
  • Transversalis fascia
  • conjoint tendon