Flashcards in GI: Hernias Deck (17):
What is a hernia?
A protrusion of part of the abdominal contents beyond the normal confines of the abdominal wall.
What is the basic structure of a hernia?
The contents of the sac - commonly bowel and omentum
The sac - a pouch of peritoneum
The coverings of the sac - the layers of the abdo wall where the hernia has passed
Where are the weaknesses in the abdominal wall? (and therefore the common sites for hernias)
What is the inguinal canal?
An oblique passage through the lower part of the abdominal wall. In males the spermatic chord passes through into the testis and in females the round ligament passes through from uterus to labium majus.
Outline the steps in the descent of the testis
The testis descend in the 7th-8th month
The processus vaginalis is a pouch of peritoneum that goes ahead of the testis
The gubernaculum is a condensed band of mesenchyme that links the testis to the developing scrotum - it condenses to pull the testis down and then regresses.
The processus vaginalis is 'pinched off' from the peritoneum to form the tunica vaginalis
Why is it important than the processus vaginalis closes during the descent of the testis?
If open it provides a pathway to the scrotum so there can be scrotal hernias
What are the boundaries of the inguinal canal?
Anterior wall - aponeurosis of external oblique
Posterior wall - transversalis fascia reinforced by conjoint tendon medially
Floor - inguinal ligament reinforced by lacuna ligament medially
Roof - internal oblique + transverse abdominis + transversalis fascia
What is the entrance and exit to the inguinal canal?
Entrance: The deep ring located on the posterior wall (transversalis fascia)
Exit: The superficial ring located on the anterior wall (aponeurosis of external oblique)
What is more common, an indirect or direct inguinal hernia?
Indirect is most common (M:F 2:1)
Describe an indirect inguinal hernia
- passes through the deep inguinal ring, through the inguinal canal then out the superficial inguinal ring
- can potentially descend into scrotum depending on where the processus vaginalis closed
- lateral to inferior epigastric vessels
Describe a direct inguinal hernia
- bulges through hesselbach's triangle in the vicinity of the superficial inguinal ring
- cant get into scrotum
- medial to inferior epigastric vessels
What are the borders of hesselbach's triangle?
Inferior - inguinal ligament
Superiolateral - inferior epigastric vessels
Superiomedial - linea semilunaris
Who is more prone to femoral hernias?
Women due to the femoral ring being broader
What is a dangerous complication of femoral hernias?
They can easily incarcerate (get stuck, irreducible) and therefore strangulate (blood supply cut off)
NB a hernia can be incarcerated without being strangulated
What are the borders of the femoral canal?
Anterior - inguinal ligament
Posterior - pectineal ligament, superior ramus of pubic bone and pectineus muscle
Medial - lacunar ligament
Lateral - femoral vein
What is a femoral hernia?
Hernia goes through the femoral ring into the femoral canal then through the saphenous opening (a weakness in the thigh fascia)