4 Hernias Flashcards
What may cause peritoneal visceral pain? (general terms)
Visceral stretching
Inflammation
Ischaemia
Describe the type of pain felt as a result of visceral pain and its accompanying symptoms:
Pain:
Diffuse/poorly defined
Often in midline
Associated symptoms:
Nausea
Vomiting
Sweating
The sympathetic nervous system mainly innervates blood vessels within gut. Describe the sympathetic outflow to the gut.
- Sympathetic nerve fibres from T5-L2 on spinal cord extend out bilaterally.
- Sympathetic nerve fibres from T5-L2 pass through sympathetic trunk (chain of ganglia)
- Sympathetic nerve fibres then coalesce to form:
- Splanchnic nerves
- Greater T5-9
- Lesser T10-11
- Least T12
- Splanchnic nerves
- Splanchnic nerves from T5-L2 synapse with prevertebral ganglia
- Post ganglionic sympathetic nerve fibres from T5-L2 go on to supply viscera
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).
- General visceral afferents activated
- Afferent impulse–>
- superior mesenteric ganglia (prevertebral)
- Continues back along least splanchnic nerve
- Through sympathetic chain
- Into dorsal horn of spine
- Converge w./ somatic afferents at spinal level T9-T10
- Brain inteprets as pain coming from T9&10 dermatomes
Define ‘a hernia’.
Protrusion of contents beyond the normal confines of its containing cavity
What are the signs/symptoms of a hernia that is NOT stuck.
- Fullness/swelling
- Gets larger when intraabdominal pressure increases
- Aches
What are the signs/symtoms of a hernia that IS stuck?
Pain
Cannot be moved
Nausea and vomiting (bowel obstruction)
Systemic problems if bowel= ischaemic
Give some causes of herniation.
- 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
What are the 3 main components of a hernia? (describe with relation to abdominal hernia)
- Sac-
- pouch of peritoneum
- Contents of sac-
- eg loops of bowel
- eg omentum
- Covering of sac-
- layer of abdominal wall
Where might we find weaknesses in the abdominal wall (potential to herniate)?
- Inguinal canal
- Femoral canal
- Umbilicus
- Previous incisions
What is the gubernaculum?
Condensed band of mesenchyme
Links inferior portion of testes to labioscrotal swelling
What can happen if the processes vaginalis fails to close?
Inguinal hernia
Scrotal hernia
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)
- 10% umbilical
- 10% incisional
- 3-5% femoral
What is the difference between an indirect and a direct hernia? (give examples)
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)
How is a hernia described?
Where it left containing cavity and relationship to vessels (eg inferior epigastric vessels)
What is hesselbachs triangle? What are its borders?
Area of potential weakness.
- Borders:
- Lateral border of rectus abdominis muscle
- Inguinal ligament
- Inferior epigastric vessels
Describe the course taken by an indirect inguinal hernia.
Passes through deep inguinal ring
–> inguinal canal
–> superficial inguinal ring
(–> potentially descends into scrotum)
Lateral to inferior epigastric vessels
Describe the course of a direct inguinal hernia.
Bulges through hesselbach’s triangle
(in vicinity of superficial inguinal ring)
Medial to inferior epigastric vessels
Is a femoral hernia more common in males or females?
Females- as femoral ring slightly wider than in males
Hernia passes through femoral ring–> empty space (femoral canal)
(Likely to get stuck)
What is an omphalocele?
Normally viscera herniate out during development- until rest of body catches up (see image)
Omphalocele:
Failure of midgut to return to abdomen during development
What is a reducible hernia?
One that can be pushed back into its orginal cavity
What is the mortality rate for a baby born with an omphalocele?
Mortality rate= high
As often associated with other genetic problems
What is gastroschisis?
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)
Describe an umbilical hernia found in infants.
Common in infants
Bulges at site of umbilicus
Not usually painful
Usually close but themselves (by age 3)
Whats the difference between an incarcerated hernia and a strangulated hernia?
Incarcerated= stuck, irreducible
Strangulated= blood supply disrupted –> necrosis
In general, which parts of the gut are supplied by each of the splanchnic nerves?
How do splanchnic nerves enter the diaphragm?
Pierce through diaphragm
