4 Hernias

Question 1

What may cause peritoneal visceral pain? (general terms)

Answer 1

Visceral stretching

Inflammation

Ischaemia

Question 2

Describe the type of pain felt as a result of visceral pain and its accompanying symptoms:

Answer 2

Pain:

Diffuse/poorly defined

Often in midline

Associated symptoms:

Nausea

Vomiting

Sweating

Question 3

The sympathetic nervous system mainly innervates blood vessels within gut. Describe the sympathetic outflow to the gut.

Answer 3

1. Sympathetic nerve fibres from T5-L2 on spinal cord extend out bilaterally.
2. Sympathetic nerve fibres from T5-L2 pass through sympathetic trunk (chain of ganglia)
3. Sympathetic nerve fibres then coalesce to form:
   
   1. Splanchnic nerves
      
      1. Greater T5-9
      2. Lesser T10-11
      3. Least T12
4. Splanchnic nerves from T5-L2 synapse with prevertebral ganglia
5. Post ganglionic sympathetic nerve fibres from T5-L2 go on to supply viscera

Question 4

Visceral pain generally follows the path of sympathetic outflow. With this in mind, describe how peri-umbilical pain (around/behind belly button) may be felt due to a distended small bowel (caecal volvulus).

Answer 4

1. General visceral afferents activated
2. Afferent impulse–>
   
   1. superior mesenteric ganglia (prevertebral)
   2. Continues back along least splanchnic nerve
   3. Through sympathetic chain
   4. Into dorsal horn of spine
   5. Converge w./ somatic afferents at spinal level T9-T10
3. Brain inteprets as pain coming from T9&10 dermatomes

Question 5

Define ‘a hernia’.

Answer 5

Protrusion of contents beyond the normal confines of its containing cavity

Question 6

What are the signs/symptoms of a hernia that is NOT stuck.

Answer 6

• Fullness/swelling
• Gets larger when intraabdominal pressure increases
• Aches

Question 7

What are the signs/symtoms of a hernia that IS stuck?

Answer 7

Pain

Cannot be moved

Nausea and vomiting (bowel obstruction)

Systemic problems if bowel= ischaemic

Question 8

Give some causes of herniation.

Answer 8

• Congenital- (descent of testes)
• Post surgery- wounds not healed (incisional hernia)
• Normal weak spots
• Anthing increasing intra-abdominal pressure:
  
  • Obesity
  • Weight lifting
  • Chronic constipation/coughing

Question 9

What are the 3 main components of a hernia? (describe with relation to abdominal hernia)

Answer 9

1. Sac-
   
   1. pouch of peritoneum
2. Contents of sac-
   
   1. eg loops of bowel
   2. eg omentum
3. Covering of sac-
   
   1. layer of abdominal wall

Question 10

Where might we find weaknesses in the abdominal wall (potential to herniate)?

Answer 10

• Inguinal canal
• Femoral canal
• Umbilicus
• Previous incisions

Question 11

What is the gubernaculum?

Answer 11

Condensed band of mesenchyme

Links inferior portion of testes to labioscrotal swelling

Question 12

What can happen if the processes vaginalis fails to close?

Answer 12

Inguinal hernia

Scrotal hernia

Question 13

The majority of abdominal hernias are inguinal (75% (50% indirect, 25% direct)). What sort of hernias make up the other 25%?

(Inguinal= more common in males)

Answer 13

• 10% umbilical
• 10% incisional
• 3-5% femoral

Question 14

What is the difference between an indirect and a direct hernia? (give examples)

Answer 14

Indirect- takes indirect route eg scrotal hernia from inguinal canal

(Lateral to inferior epigastric vessels)

Direct- inguinal hernia straight through abdominal wall

(medial to inferior epigastric vessels)

Question 15

How is a hernia described?

Answer 15

Where it left containing cavity and relationship to vessels (eg inferior epigastric vessels)

Question 16

What is hesselbachs triangle? What are its borders?

Answer 16

Area of potential weakness.

• Borders:
  
  • Lateral border of rectus abdominis muscle
  • Inguinal ligament
  • Inferior epigastric vessels

Question 17

Describe the course taken by an indirect inguinal hernia.

Answer 17

Passes through deep inguinal ring

–> inguinal canal

–> superficial inguinal ring

(–> potentially descends into scrotum)

Lateral to inferior epigastric vessels

Question 18

Describe the course of a direct inguinal hernia.

Answer 18

Bulges through hesselbach’s triangle

(in vicinity of superficial inguinal ring)

Medial to inferior epigastric vessels

Question 19

Is a femoral hernia more common in males or females?

Answer 19

Females- as femoral ring slightly wider than in males

Hernia passes through femoral ring–> empty space (femoral canal)

(Likely to get stuck)

Question 20

What is an omphalocele?

Answer 20

Normally viscera herniate out during development- until rest of body catches up (see image)

Omphalocele:

Failure of midgut to return to abdomen during development

Question 21

What is a reducible hernia?

Answer 21

One that can be pushed back into its orginal cavity

Question 22

What is the mortality rate for a baby born with an omphalocele?

Answer 22

Mortality rate= high

As often associated with other genetic problems

Question 23

What is gastroschisis?

Answer 23

Defect in ventral abdominal wall

Viscera not covered in peritoneum

Exposed to amniotic fluid

Inflamed gut/short gut/intestinal atresia

(defect can often be closed at birth)

(better survival than omphalocele as less genetic complications)

Question 24

Describe an umbilical hernia found in infants.

Answer 24

Common in infants

Bulges at site of umbilicus

Not usually painful

Usually close but themselves (by age 3)

Question 25

Whats the difference between an incarcerated hernia and a strangulated hernia?

Answer 25

Incarcerated= stuck, irreducible Strangulated= blood supply disrupted --\> necrosis

Question 26

In general, which parts of the gut are supplied by each of the splanchnic nerves?

Answer 26

Question 27

How do splanchnic nerves enter the diaphragm?

Answer 27

Pierce through diaphragm