GI: Hernias

Question 1

What is a hernia?

Answer 1

A protrusion of part of the abdominal contents beyond the normal confines of the abdominal wall.

Question 2

What is the basic structure of a hernia?

Answer 2

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

Question 3

Where are the weaknesses in the abdominal wall? (and therefore the common sites for hernias)

Answer 3

Inguinal canal
Femoral canal
Umbilicus
Previous incisions

Question 4

What is the inguinal canal?

Answer 4

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.

Question 5

Outline the steps in the descent of the testis

Answer 5

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

Question 6

Why is it important than the processus vaginalis closes during the descent of the testis?

Answer 6

If open it provides a pathway to the scrotum so there can be scrotal hernias

Question 7

What are the boundaries of the inguinal canal?

Answer 7

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

Question 8

What is the entrance and exit to the inguinal canal?

Answer 8

Entrance: The deep ring located on the posterior wall (transversalis fascia)
Exit: The superficial ring located on the anterior wall (aponeurosis of external oblique)

Question 9

What is more common, an indirect or direct inguinal hernia?

Answer 9

Indirect is most common (M:F 2:1)

Question 10

Describe an indirect inguinal hernia

Answer 10

• 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

Question 11

Describe a direct inguinal hernia

Answer 11

• bulges through hesselbach’s triangle in the vicinity of the superficial inguinal ring
• cant get into scrotum
• medial to inferior epigastric vessels

Question 12

What are the borders of hesselbach’s triangle?

Answer 12

Inferior - inguinal ligament
Superiolateral - inferior epigastric vessels
Superiomedial - linea semilunaris

Question 13

Who is more prone to femoral hernias?

Answer 13

Women due to the femoral ring being broader

Question 14

What is a dangerous complication of femoral hernias?

Answer 14

They can easily incarcerate (get stuck, irreducible) and therefore strangulate (blood supply cut off)
NB a hernia can be incarcerated without being strangulated

Question 15

What are the borders of the femoral canal?

Answer 15

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

Question 16

What is a femoral hernia?

Answer 16

Hernia goes through the femoral ring into the femoral canal then through the saphenous opening (a weakness in the thigh fascia)

Question 17

What is an epigastric hernia?

Answer 17

Herniates through the linea alba- usually starts with small pouch of fat then chronic straining forces more fat out which can pull some peritoneum.