GI4 - Abdominal Walls & Hernias

Question 1

4 features of visceral pain

Pain Triggers x3
Pain Type
Pain Regions x3
Secondary Symptoms x2

Answer 1

1.) Pain Triggers - visceral stretching, inflammation, and ischaemia

2. ) Pain Type - poorly defined and often midline
   - poorly defined because prevertebral ganglia contains one post-ganglionic fibre for each organ but multiple pre-ganglionic fibres
   - midline because of the bilateral nature of the nerves
3. ) Pain Regions - depends on which ganglia supplies the organ
   - celiac = epigastric, superior mesenteric = umbilical, inferior mesenteric = suprapubic

4.) Secondary Symptoms - N/V, sweating

Question 2

4 features of the sympathetic outflow

Nerve Roots
Greater Splanchnic Nerve
Lesser Splanchnic Nerve
Least Splanchnic Nerve

Answer 2

1. ) Nerve Roots - T5-L2
   - white rami communicantes carry preganglionic fibres from spinal nerve to the sympathetic trunk
   - splits into splanchnic nerves
2. ) Greater Splanchnic Nerve - T5-T9 synapses unto celiac ganglia which innervates the foregut
3. ) Lesser Splanchnic Nerve - T10-11 synapses unto superior mesenteric ganglia which innervates the midgut
4. ) Least Splanchnic Nerve - T12 synapses unto inferior mesenteric ganglia which innervates the hindgut

Question 3

What are the 2 main causes of hernias?

Give examples

Answer 3

1. ) Weakness in the Containing Cavity
   - can be congenital, post-surgery (incisional hernia),
   - normal points of weakness: inguinal and femoral canal, umbilicus
2. ) Raised Intra-abdominal Pressure
   - obesity, weightlifting, chronic constipation/coughing
3. ) Others
   - cirrhosis, ascites, peritoneal dialysis
   - smokers, carcinamatosis
   - AAA, abnormal collagen

Question 4

Clinical Features of Inguinal Hernias

Reducible
Incarcerated
Strangulated

Answer 4

1. ) Reducible - swellings and aches
   - generally painless but can be tender to palpation
   - can disappar when minimal pressure or lying down
   - cough impulse: expands during coughing (↑pressure) due to pushing contents through wall defect
2. ) Incarcerated - contents of the hernia are unable to return to the original cavity
   - painful, tender, and erythematous
   - no cough impulse
3. ) Strangulated - compromised blood supply causing ischaemic bowel, surgical emergency
   - very painful, irreducible, tender, tense lump
   - may be signs of bowel obstruction or necrosis
   - no cough impulse

Question 5

What 3 things does a hernia consist of?

Answer 5

1. ) The Sac - a pouch of peritoneum
2. ) Contents of the Sac - any structure found within the abdominal cavity e.g. loops of bowel, omentum
3. ) Coverings of the Sac - layers of the abdominal wall the hernia has passed through

Question 6

4 features of the inguinal canal

Function
Contents x4
Important Landmarks x2
Inguinal and Scrotal Hernias

Answer 6

1. ) Function - pathway for structures to pass through the abdominal wall to the external genitalia
2. ) Contents - spermatic cords (males), round ligament (females), ilioinguinal nerve, genital branch of the genitofemoral nerve
3. ) Important Landmarks - inferior epigastric vessels, hesselbachs triangle
4. ) Inguinal and Scrotal Hernias - created due to the failure of the processus vaginalis to degenerate
   - partial degeneration = inguinal hernia
   - no degeneration = scrotal hernia

Question 7

What are the boundaries of the inguinal canal?

Anterior, posterior, roof, floor

Answer 7

Anterior - aponeurosis of external oblique
- superficial ring is a gap in the external oblique

Posterior - transversalis fascia, conjoint tendon (medially)
- deep ring is a gap in the transversalis fascia

Roof - internal oblique, transversus abdominis, transversalis fascia

Floor - inguinal ligament
- thickened by lacunar ligament medially

Question 8

Classification of Inguinal Hernias

Indirect
Direct
Theoretical Distinction
Practical Differentiation
Distinction of Type
Prevalence

Answer 8

1. ) Indirect - go through deep ring and superficial ring
   - caused by failure of processus vaginalis to regress
   - can extend into scrotum (can get above it)
   - reduces superolaterally and posteriorly
2. ) Direct - doesn’t go through deep ring but goes straight through the posterior wall
   - caused by weakening of the abdominal musculature
   - reduces superiorly and posteriorly
3. ) Distinction - the point the hernia leaves its containing cavity describes if its indirect or direct
   - neck of the swelling is superior and medial to the pubic tubercle (femoral hernia is inferior and lateral)
   - indirect: lies lateral to the inferior epigastric vessels
   - direct: lies medial to the inferior epigastric vessels
4. ) Differentiation
   - reduce hernia, apply pressure over the deep inguinal ring, and then ask the patient to cough
   - hernia protrudes = direct, if not = indirect
5. ) Prevalence - approx 75% of all abdominal hernias
   - 50% indirect (mainly right sided), 25% Direct
   - 20% are bilateral

Question 9

What is omphalocele and gastroschisis?

Answer 9

Omphalocele - failure of the midgut to return to the abdomen during development

• viscera persists outside the abdominal cavity within umbilical ring
• gut has a chance to develop normally so feeding can commence

Gastroschisis - defect in ventral abdominal wall

• abdominal viscera not covered in peritoneum so tend to get problems with gut development and problems with feeding
• survival is better than omphalocele due to less genetic complications

Question 10

General Features of Femoral Hernias

Anatomy
Prevalence
Risk Factors

Answer 10

1. ) Femoral Canal Borders
   - superior border: femoral ring (covered by septum)
   - anterior: inguinal ligament, medial: lacunar ligament
   - lateral: femoral vein, posterior: pectineal ligament, pectineus, superior ramus of pubic bone
   - rigid borders ↑complications of femoral hernias
2. ) Prevalence - relatively uncommon but important due to high rate of strangulation (due to narrow neck)
   - more common in women (3:1) due to having a wider bony pelvis, it is very rare in children
3. ) Risk Factors
   - female, pregnancy, ↑age, ↑intra-abdominal pressure

Question 11

Management of Femoral Hernias

Clinical Features
Investigations
Surgical Interventions

Answer 11

1. ) Clinical Features - small lump in groin
   - usually asymptomatic but 30% of cases present as an emergency (obstruction or strangulation)
   - unlikely to be reducible (tightness of femoral ring)
   - infero-lateral to pubic tubercle
2. ) Investigations
   - routine pre-op investigations: all need surgery
   - imaging: USS or CT abdo-pelvo
   - can be surgical explored if any doubt
3. ) Surgical Intervention - reduce the hernia and narrow the femoral ring with sutures or a mesh plug
   - low approach: inscision below inguinal ligament (safer but less room to manouevre)
   - high approach: incision above is preferred in emergencies due to easy access to small bowel