Lecture 3 - Hernias Flashcards
What is a hernia?
What are the signs + symptoms of an incarcerated & non-incarcerated hernia?
A protrusion of part of the abdominal contents beyond the normal abdominal wall.
Non-incarcerated (not-stuck):
- Fullness/swelling
- Can push it back in
- Aches
Incarcerated (stuck):
- Pain
- Cannot be moved
- Nausea/vomiting (due to bowel obstruction)
- Systemic problems if bowel becomes ischaemic
What are the main causes of hernias?
2 main reasons:
1) Weaknesses in containing cavity - e.g.: congenitally related, post-op etc.
2) Anything increasing intra-abdominal pressure - e.g.: weigh lifting, chronic coughing, obesity
What are the 3 parts a hernia consists of?
1) The sac - a pouch of peritoneum (parietal)
2) Contents of the sac - any structure within abdominal cavity (loops of bowel/omentum commonly)
3) Coverings of the sac - consisting of the layers of the abdominal wall through which the hernia has passed
Abdominal hernias often occur due to natural weaknesses in the abdominal wall such as the inguinal cancel. What is the inguinal canal?
- Oblique passage through lower part of abdominal wall
- In males structures pass through abdomen to testis
- Has an entrance (deep inguinal ring) & an exit (superficial inguinal ring)
- Inguinal ligament is floor of inguinal canal
Explain when and how the testis descend in males?
- In 7th-8th month of life
- Gubernaculum (condensed band of mesenchyme condenses, pulls testis downwards towards scrotum.
- Processus vaginalis (pouch of peritoneum) obliterates to form the tunica vaginalis
How do inguinal & scrotal hernias develop embryologically in relation to descent of the testis?
- If the processus vaginalis doesn’t close up/obliterate, end up with a root from the peritoneal cavity
- A connection between peritoneal cavity and scrotum which can lead to hernias into inguinal canal (if obliteration is partial) or scrotal hernias (if no obliteration)
What are the boundaries of the inguinal canal? (floor, roof, posterior wall & anterior wall)
Use MALT -
Roof = Internal oblique & transverse abdominus muscles Floor = Inguinal ligament + lacunar ligament Anterior = External oblique aponeurosis Posterior = Transversialis fascia & conjoint tendon (medially)
M = roof, A = Anterior, L = Floor, T = Posterior
Inguinal hernias account for 75% of all abdominal hernias. What 2 kinds of inguinal hernias are there?
1) Indirect (50%) - go through inguinal canal. M>F 7:1, mainly right sided. Passes through deep inguinal ring, then inguinal canal, then superficial inguinal ring. Depending on where processus vaginalis was obliterated can potentially descend into scrotum.
2) Direct (25%) - Bulges directly out of abdominal cavity through Hesselbach’s triangle (generally in vicinity of superficial inguinal ring)
Therefore, what is the anatomical difference between an indirect and direct inguinal hernia?
Indirect - lateral to inferior epigastric vessels, entering at the deep inguinal ring
Direct - medial to inferior epigastric vessels, emerging out at hesselbach’s triangle
What is omphalocele and gastroschisis and how do they occur?
Omphalocele = failure of midgut to return to abdomen during development. Viscera persists outside of abdominal cavity within umbilical ring, viscera covered in peritoneum.
Gastroschisis = defect in ventral abdominal wall. Abdominal viscera not covered in peritoneum, exposed to amniotic fluid. Survival better than omphalocele.
When are umbilical hernias common?
How are they treated?
- Commonly found in infants, hernias bulge at site of umbilicus
- Not usually painful, 80-90% close by age 3 so usually left alone unless abnormally large or painful
What are para-umbilical hernias?
What are the risk factors?
What are the symptoms?
- Acquired adult umbilical hernias, goes through linea alba region
- F>M, obesity
- Can lead to strangulation (blood supply disrupted which can lead to necrosis)
- Symptoms based on what happens if loops of bowel are strangulated - e.g.: pain, vomiting, sepsis
