Inguinal Canal Flashcards
What is the inguinal canal?
Oblique intermuscular passage in the lower part of the anterior abdominal wall, situated just above the medial half of the inguinal ligament
Direction of the inguinal canal?
Downwards, forwards and medially
Length of the inguinal canal
4cm/1.5in
Extent of the inguinal canal
Extends from the deep inguinal ring to the superficial inguinal ring
What is the deep inguinal ring?
The deep inguinal ring is an oval opening in the fascia transversalis
Location of the deep inguinal ring
Situated 1.2 cm above the mid inguinal point, and immediately lateral to the stem of the inferior epigastric artery
What is the superficial inguinal ring?
The superficial inguinal ring is a triangular gap in the external oblique aponeurosis
Shaped like an obtuse angled triangle
Formation of the superficial inguinal ring
The base of the triangle is formed by the pubic crest
Boundaries of the anterior wall of the inguinal canal
Skin
Superficial fascia
External oblique aponeurosis
Boundaries of the antero-lateral 1/3rd of the inguinal canal
Fibers of the internal oblique muscle
Boundaries of the posterior wall of the inguinal canal
Fascia transversalis
Extraperitoneal tissue
Parietal peritoneum
Boundaries of the postero-lateral 2/3rds of the inguinal canal
The conjoint tendon
At its medial end by the reflected part of the inguinal ligament
The roof of the inguinal canal is formed by …
the arched fibers of the internal oblique and transversus abdominis muscles
The floor of the inguinal canal is formed by …
the grooved upper surface of the inguinal ligament; and at the medial end by the lacunar ligament
Describe the difference in the inguinal canal between men and women
Inguinal canal is larger in males than females
Why is the lower part of the anterior abdominal wall weaker?
Presence of inguinal canal
How is the weakness of the anterior abdominal wall compensated for?
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
What is an external hernia?
Protrusion of any of the abdominal contents through any of its walls
What is an internal hernia?
Intestine or omentum protrudes into the abdominal cavity itself
