Inguinal canal and hernias

Question 1

Where is the midingual point?

Answer 1

Midpoint between ASIS and the pubic symphysis

Question 2

Where is the midpoint of the inguinal ligament?

Answer 2

Midpoint between ASIS and the pubic tubercle

Question 3

Where can the femoral artery be palpated?

Answer 3

Midingual point +/- 1 cm

Approximate marker for deep inguinal ring

Question 4

Which age groups are umbilical hernias most commonly seen in?

Answer 4

Newborns

Question 5

Where do inguinal hernias tend to originate?

Answer 5

Superior/ superior + medial to the pubic tubercle

[Pubic tubercle should always be used as a reference point and important to identify origin of sac rather than most inferior aspect]

Question 6

How might you examine whether an inguinal hernia contains a loop of small intestine?

Answer 6

Auscultate for bowel sounds

Question 7

What are the borders of the inferior lumbar (Petit’s) triangle and which age group most commonly herniates this site?

Answer 7

External oblique, Latissimus Dorsi and Iliac Crest

Most common in males, aged 50-70

Question 8

What are the borders of the superior lumber triangle?

Answer 8

Rib 12, Internal oblique and Quadratus Lomborum

Question 9

Why are inguinal hernias more common in men?

Answer 9

Descent of testicles through the inguinal canal to the scrotum leaves a weak spot (testicles develop in a retroperitoneal position on the posterior abdominal wall before descending through the anterior abdominal wall)

[Potential route for herniation = processus vaginalis]

Question 10

What is the contents of the inguinal canal in females?

Answer 10

Round ligament of uterus (emerges from superficial ring)
Lymphatics from the uterus
Ilioinguinal nerve
Genital branch of genitofemoral nerve

Question 11

What is the contents of the inguinal canal in males?

Answer 11

Spermatic cord (emerges from superficial ring) and contents
Ilioinguinal nerve
Genital branch of genitofemoral nerve

Question 12

Where is the deep inguinal ring located?

Answer 12

Inner surface of abdominal wall - an invagination of the transversalis fascia
Located between the midinguinal point and the midpoint of the midinguinal ligament

Question 13

Where is the superficial inguinal ring located?

Answer 13

In external oblique aponeurosis, supero-lateral to the pubic tubercle

Question 14

What nerves are at risk of damage during inguinal canal surgery?

Answer 14

Ilioinguinal (causing groin pain) - passes into inguinal canal laterally (not through deep ring)
Iliohypogastric

Question 15

What forms the borders of the inguinal canal?

Answer 15

Floor = inguinal ligament
Anterior wall = external oblique aponeurosis
Roof = internal oblique and transversus abdominis aponeuroses (joint to form conjoint tendon as they reach the pubic tubercle)
Posterior wall = transversalis fascia

Question 16

What artery is on the inner surface of the abdominal wall, forming a useful landmark for inguinal hernias?

Answer 16

Inferior epigastric artery

Question 17

What is the difference between a direct and indirect inguinal hernia?

Answer 17

Direct hernia pass directly through the anterior abdominal wall into the inguinal canal and through the superficial inguinal ring - sits medially to the inferior epigastric artery - due to weakness of conjoint tendon

Indirect hernia passes through the deep inguinal ring, inguinal canal and superficial inguinal ring (via an indirect route) and sits laterally to the inferior epigastric artery

[Indirect more common in males]

Question 18

What is Hesselbach’s triangle?

Answer 18

A weak region between the rectus abdominus, the inguinal ligament and the inferior epigastric artery (that can only be seen on the inside of the abdominal wall) delineating the region of bulging with a direct inguinal hernia

Question 19

Where does the ilioinguinal nerve supply sensory innervation to in males?

Answer 19

Anterior scrotum and proximal penis