Hernias

Question 1

What can lead to visceral pain, how would you describe it and what often accompanies it?

Answer 1

Results from visceral:
Stretching, inflammation, ischaemia

Pain is:
Diffuse/ poorly defined, often midline

Accompanied often with: nausea, vomiting, sweating

Question 2

Describe sympathetic outflow to visceral pleura

Answer 2

T5-L2 (preganglionic) pass through paravertebral sympathetic trunk without synapsing

form abdominopelvic presynaptic splanchnic nerves:
Greater splanchnic Nerve (from T5-9)5
Lesser splanchnic nerve (T10-11)2
Least (T12)1

These synapse with prevertebral ganglia (coeliac, Renal, superior mesenteric, inferior mesenteric and others)

extend to viscera (postganglionic)

Mainly innervate blood vessels

Question 3

Describe how visceral pain from the midgut when a patient has a caecal volvulus (torsion of caecum) follows the reverse path of sympathetic outflow

Answer 3

Distended small bowel -> general visceral afferent activated -> signals travel back to superior mesenteric ganglia -> continues along least splanchnic Nerve -> passes through sympathetic trunk -> into dorsal horn of spine -> converges with somatic afferent sat that spine level (T9-20) -> Brian interprets pain to be coming from T9-10 dermatomes = peri-umbilical pain

Question 4

What is a hernia? What are they composed of?

Answer 4

A protrusion of an anatomical structure beyond the confines of its containing cavity

Consists of three parts:

• The sac (peritoneum)
• Contents of the sac (whatever peritoneum surrounds e.g. omentum, loops of bowel)
• Coverings of the sac (layers of abdo wall that hernia passes)

Question 5

Differences between incarcerated and non-incarcerated hernias

Answer 5

Incarcerated = trapped/ stuck: pain, can’t be moved, nausea, vomiting, systemic problems (if bowel has become ischaemia), can lead to strangulation

Non-incarcerated: fullness/ swelling, gets larger when intra-abdominal pressure increase, aches

Question 6

Causes of hernias

Answer 6

Congenitally related,

Post surgery where wounds have not healed adequately (incisional hernia) around scar is weak,

Normal points of weakness,

Anything that increases intra-abdominal pressure:
Obesity, weightlifting, chronic constipation/ coughing

Question 7

What is the inguinal canal? What structures pass through it?

Answer 7

Oblique passage through lower part of abdominal wall

Contents:
Ilioinguinal Nerve

Males:
Spermatic cord and its coverings (vas deferens, testicular artery, pampiniform plexus, cremasteric artery, artery to vas, sympathetic nerves, cremaster muscle and lymphatics)
,
Females: round ligament (uterus-> labia majora) l

Question 8

Normal descent of the testis

Answer 8

7th-8th month:
The processus vaginalis (pouch of peritoneum) guides the way before the testis, then loses connection to the peritoneum and is obliterated (Some left as tunica vaginalis)

Gubernaculum (band of mesenchyme) guides testis down to developing scrotum after PV

Question 9

What happens if processus vaginalis doesn’t close? (Patent)

Answer 9

Fluid can collect in the pouch (hydrocele)

connection of peritoneal cavity and scrotum where hernias can occur (inguinal or scrotal)

Question 10

Structure of inguinal canal

Answer 10

Layers of posterior wall: skin, superficial fascia, deep fascia, external oblique aponeurosis rolls inferiorly ->

inguinal ligament (floor IC) above conjoint ligament (reinforces back wall) and superior ramus of pubis

Then internal oblique - arching fibres form roof (+ arching fibres of transversalis abdominus)

Then transversalis fascia = posterior wall

Question 11

Boundaries of inguinal canal

Answer 11

Roof = arching fibres & aponeurosis of internal oblique and transversalis abdominus

Floor= inguinal ligament (+ lacunar ligament medially)

posterior wall = transversalis fascia (+ conjoint tendon medially) (deep ring entrance)

Anterior wall = aponeurosis of external oblique (superficial ring exit)

Question 12

What’s the difference between direct and indirect inguinal hernias?

Answer 12

Indirect - goes through inguinal canal (through deep and superficial ring)

Direct- doesn’t go through inguinal canal (Hesselbachs triangle and then superficial ring generally)

Question 13

Types of inguinal hernia

Answer 13

50% indirect 
25% direct 
10% umbilical
10% incisional 
3-5% femoral

Question 14

Indirect and direct hernias in relation to inferior epigastric vessels

Answer 14

Indirect- lateral to epigastric vessels

Direct- medial

Question 15

Boundaries of hesselbachs triangle

Answer 15

Medial: Rectus abdominus muscle

Superolateral: inferior epigastric vessels

Inferior: inguinal ligament,

Question 16

Why are femoral hernias more common in women?

Answer 16

More common in females Bc femoral ring wider but still rare

Easily incarcerated

Question 17

Contents of femoral canal

Answer 17

Empty space
Lymphatics
Loose Ct

Question 18

Boundaries of femoral canal

Answer 18

Medial- lacunar ligament
Lateral- femoral vein
Anterior - inguinal ligament
Posterior- pectineal ligament, superior ramus of pubic bone, pectineus muscle

Question 19

Contents of femoral triangle

Answer 19

NAVEL

```
Femoral Nerve
femoral Artery
Femoral Vein
Canal:
Empty space
Lymphatics
~~~

Question 20

What is omphalocele?

Answer 20

Failure of the midgut to return to the abdomen during development

Viscera persist outside the abdominal cavity within umbilical ring
Abdo cavity May not grow to correct size to accommodate viscera
Viscera are covered in peritoneum

Gut has a chance to develop relatively normally

Often associated with other genetic problems so mortality rate is high

Question 21

What is gastroschisis?

Answer 21

Defect in ventral abdominal wall

Abdominal viscera NoT covered in peritoneum - exposed to amniotic fluid

Tend to get problems with gut development (intestinal atresia, short/ inflamed gut, problems with feeding)

Survival better bc less genetic complaints

Question 22

What is an umbilical hernia?

Answer 22

Community found in infants

Hernia at site of umbilicus

Usually asymptomatic
80-90% close by 3yrs

Question 23

What is a para-umbilical hernia? What are the symptoms?

Answer 23

Acquired as an adult

Goes through lines alba (where aponeurosis meet) in region of umbilicus
F>M
Obesity (or anything increasing intra-abdo pressures
Risk of strangulation as often small defect

Symptoms: If loops of bowel get trapped: pain, vomiting, sepsis, May get incarcerated or strangulated (-> necrosis)