Hernias Flashcards
What can lead to visceral pain, how would you describe it and what often accompanies it?
Results from visceral:
Stretching, inflammation, ischaemia
Pain is:
Diffuse/ poorly defined, often midline
Accompanied often with: nausea, vomiting, sweating
Describe sympathetic outflow to visceral pleura
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
Describe how visceral pain from the midgut when a patient has a caecal volvulus (torsion of caecum) follows the reverse path of sympathetic outflow
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
What is a hernia? What are they composed of?
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)
Differences between incarcerated and non-incarcerated hernias
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
Causes of hernias
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
What is the inguinal canal? What structures pass through it?
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
Normal descent of the testis
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
What happens if processus vaginalis doesn’t close? (Patent)
Fluid can collect in the pouch (hydrocele)
connection of peritoneal cavity and scrotum where hernias can occur (inguinal or scrotal)
Structure of inguinal canal
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
Boundaries of inguinal canal
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)
What’s the difference between direct and indirect inguinal hernias?
Indirect - goes through inguinal canal (through deep and superficial ring)
Direct- doesn’t go through inguinal canal (Hesselbachs triangle and then superficial ring generally)
Types of inguinal hernia
50% indirect 25% direct 10% umbilical 10% incisional 3-5% femoral
Indirect and direct hernias in relation to inferior epigastric vessels
Indirect- lateral to epigastric vessels
Direct- medial
Boundaries of hesselbachs triangle
Medial: Rectus abdominus muscle
Superolateral: inferior epigastric vessels
Inferior: inguinal ligament,
Why are femoral hernias more common in women?
More common in females Bc femoral ring wider but still rare
Easily incarcerated
Contents of femoral canal
Empty space
Lymphatics
Loose Ct
Boundaries of femoral canal
Medial- lacunar ligament
Lateral- femoral vein
Anterior - inguinal ligament
Posterior- pectineal ligament, superior ramus of pubic bone, pectineus muscle
Contents of femoral triangle
NAVEL
```
Femoral Nerve
femoral Artery
Femoral Vein
Canal:
Empty space
Lymphatics
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What is omphalocele?
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
What is gastroschisis?
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
What is an umbilical hernia?
Community found in infants
Hernia at site of umbilicus
Usually asymptomatic
80-90% close by 3yrs
What is a para-umbilical hernia? What are the symptoms?
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)
