Inguinal Canal

Question 1

What is the inguinal canal?

Answer 1

Oblique intermuscular passage in the lower part of the anterior abdominal wall, situated just above the medial half of the inguinal ligament

Question 2

Direction of the inguinal canal?

Answer 2

Downwards, forwards and medially

Question 3

Length of the inguinal canal

Answer 3

4cm/1.5in

Question 4

Extent of the inguinal canal

Answer 4

Extends from the deep inguinal ring to the superficial inguinal ring

Question 5

What is the deep inguinal ring?

Answer 5

The deep inguinal ring is an oval opening in the fascia transversalis

Question 6

Location of the deep inguinal ring

Answer 6

Situated 1.2 cm above the mid inguinal point, and immediately lateral to the stem of the inferior epigastric artery

Question 7

What is the superficial inguinal ring?

Answer 7

The superficial inguinal ring is a triangular gap in the external oblique aponeurosis
Shaped like an obtuse angled triangle

Question 8

Formation of the superficial inguinal ring

Answer 8

The base of the triangle is formed by the pubic crest

Question 9

Boundaries of the anterior wall of the inguinal canal

Answer 9

Skin
Superficial fascia
External oblique aponeurosis

Question 10

Boundaries of the antero-lateral 1/3rd of the inguinal canal

Answer 10

Fibers of the internal oblique muscle

Question 11

Boundaries of the posterior wall of the inguinal canal

Answer 11

Fascia transversalis
Extraperitoneal tissue
Parietal peritoneum

Question 12

Boundaries of the postero-lateral 2/3rds of the inguinal canal

Answer 12

The conjoint tendon
At its medial end by the reflected part of the inguinal ligament

Question 13

The roof of the inguinal canal is formed by …

Answer 13

the arched fibers of the internal oblique and transversus abdominis muscles

Question 14

The floor of the inguinal canal is formed by …

Answer 14

the grooved upper surface of the inguinal ligament; and at the medial end by the lacunar ligament

Question 15

Describe the difference in the inguinal canal between men and women

Answer 15

Inguinal canal is larger in males than females

Question 16

Why is the lower part of the anterior abdominal wall weaker?

Answer 16

Presence of inguinal canal

Question 17

How is the weakness of the anterior abdominal wall compensated for?

Answer 17

The flap valve mechanism: The obliquity of the inguinal canals mean that when the intra-abdominal pressure rises, the anterior and posterior walls of the canal are approximated, thus obliterating the passage.
Shutter mechanism of the internal oblique: The internal oblique muscle forms the anterior wall, the roof, and the posterior wall of the canal. When it contracts the roof is approximated to the floor, like a shutter.
The superficial inguinal ring is guarded from behind by the conjoint tendon and by the reflected part of the inguinal ligament
The deep inguinal ring is guarded from the front by the fleshy fibres of the internal oblique

Question 18

What is an external hernia?

Answer 18

Protrusion of any of the abdominal contents through any of its walls

Question 19

What is an internal hernia?

Answer 19

Intestine or omentum protrudes into the abdominal cavity itself