Inguinal canal and hernias

Question 1

Define hernia

Answer 1

Protrusion of a tissue or organ through a retaining tissue

Question 2

What does the inguinal ligament span between?

Answer 2

ASIS and pubic tubercle

Question 3

At what point does the external iliac artery become the femoral artery?

Answer 3

When it passes behind the inguinal ligament into the thigh

Question 4

Where is the mid-inguinal point?

Where is the midpoint of inguinal ligament?

Answer 4

Mid-inguinal point: 50% of way between ASIS and pubic symphysis

Midpoint of inguinal ligament: 50% of way between ASIS and pubic tubercle.

Question 5

Where does the pulsation of the femoral artery sit?

What is this an approximate marker for?

Answer 5

+/- 1cm from mid inguinal point

Approximate marker for the location of the deep inguinal ring (entrance to the inguinal canal)

Question 6

Where are the origins of a femoral and inguinal hernia?

Answer 6

Inguinal: above/ above and medial to the pubic tubercle

Femoral: below the level of the pubic tubercle

Question 7

Name some common abdominal wall hernias

Who are they most common in?

Answer 7

Umbilical: most common in newborns and women post pregnancy (separation of rectus abdominis)

Inguinal: most common in males as testicles descend through the inguinal canal, larger aperture in males.

Femoral: more common in females due to wider pelvis

Question 8

Where do some common posterior abdominal wall hernias occur?

Answer 8

Inferior lumbar triangle

Superior lumbar triangle

Question 9

What are the borders of the inferior lumbar triangle?

Answer 9

Lateral border: external oblique

Medial border: latissimus dorsi

Inferior border: iliac crest

Question 10

What are the borders of the superior lumbar triangle?

Answer 10

Superior border: rib 12

Lateral border: internal oblique

Medial border: quadratus lumborum

Question 11

What forms the deep inguinal ring?

Where is it located?

Answer 11

Invagination of the transversalis fascia

Located between midpoint of inguinal ligament and mid inquinal point 1cm above inguinal ligament.

Question 12

What forms the superficial inguinal ring?

Where is it located?

What emerges through it?

Answer 12

External oblique aponeurosis

Located superolateral to the pubic tubercle

Point of emergence for spermatic cord in males and round ligament and its coverings in females.

Question 13

What are the contents of the female inguinal canal?

Answer 13

Round ligament of uterus

Lymphatics from uterus

Ilioinguinal nerve

Genital branch of genitofemoral nerve

Question 14

What are the contents of the male inguinal canal?

Answer 14

Spermatic cord and its contents

Ilioinguinal nerve

Genital branch of femoral nerve

Question 15

Where do the testicles and ovaries develop?

Are they intra or retroperitoneal at this stage?

Answer 15

On the posterior abdominal wall

Retroperitoneal

Question 16

What is the tunica vaginalis?

Answer 16

Fold of peritoneum that descends with the testes through the inguinal canal. It is retained in males and allows free movement of the testes in the scrotum,

Question 17

What is the processus vaginalis?

Answer 17

The double layered loop of peritoneum pulled through the inguinal canal along with the testes. Gives rise to the tunica vaginalis.

Normally fuses but can remain patent causing predisposition to inguinal hernias.

Question 18

What are the borders of the inguinal canal?

Answer 18

Anterior: external oblique aponeurosis

Posterior: transversalis fascia

Roof: transversalis fascia, transversus abdominis and internal oblique

Floor: inguinal ligament

Question 19

How do the internal oblique and transversus abdominis provide support to the superficial inguinal ring?

What do they form?

Answer 19

They arch over the top of the inguinal canal and attach to the pubic tubercle. They travel infero-medially, providing support to the posterior wall.

They form the conjoint tendon

Question 20

What is a direct inguinal hernia?

Where do they always occur?

Answer 20

Peritoneal sac passes through to the inguinal canal via the posterior wall out of the superficial ring. Often caused by weakness of the conjoint tendon.

Occur medial to the inferior epigastric artery in Hesselbach’s triangle.

Question 21

What is an indirect inguinal hernia?

Where do they always occur?

Answer 21

Peritoneal sac passes through deep inguinal ring into the inguinal canal and out of the superficial inguinal ring.

Occur lateral to inferior epigastric artery, often due to failure of the processus vaginalis to fuse. Extend of protrusion depends on the degree of processus vaginalis that remains.

Question 22

What are the borders of Hesselbach’s triangle?

Answer 22

Lateral: inferior epigastric artery

Medial: rectus abdominis

Lower: inguinal ligament

Question 23

What is at risk in inguinal canal/lower abdominal wall surgery?

What can be the consequences if they are damaged?

Answer 23

• Iliohypogastric nerve
  
  • Damage= muscle paralysis/weakness in lower abdomen and conjoint tendon; predisposition to direct hernias.
• Ilioinguinal nerve (most at risk- travels through part of inguinal canal)
  
  • Changes/loss of sensation to anterior scrotum and proximal penis/ anterior labia majora.

Question 24

How does the ilioinguinal nerve pass through the inguinal canal?

Answer 24

Enters laterally (not through the deep ring) and exits through the superficial canal.