Inguinal Canal

Question 1

What is the IC?

Answer 1

The inguinal canal is a short passage that extends inferiorly and medially through the inferior part of the abdominal wall.

Question 2

Location of the IC

Answer 2

It is superior and parallel to the inguinal ligament, and between the deep and superficial inguinal rings

Question 3

Why does the IC exist?

Answer 3

The canal serves as a pathway by which structures can pass from the abdominal wall to the external genitalia

Question 4

What produced the IC?

Answer 4

The inguinal canal is the pathway by which the testes (in an individual with an XY karyotype) leave the abdominal cavity and enter the scrotum.

Question 5

What is the gubernaculum?

Answer 5

A fibrous cord of tissue called the gubernaculum attaches the inferior portion of the gonad to the future scrotum or labia, and guides them during their descent

Question 6

What is the length of the IC?

Answer 6

Adult - 4cm

Newborn - 0, rings are super-imposed

Question 7

What is the fate of the gubernaculum in the adult?

Answer 7

The gubernaculum becomes two structures in the adult: the ovarian ligament and round ligament of uterus

Question 8

Posterior wall of IC

Answer 8

Transversalis fascia

Conjoint tendon

Question 9

Anterior wall of IC

Answer 9

Aponeurosis of the external oblique, reinforced by the internal oblique muscle laterally.

Question 10

Roof of IC

Answer 10

Transversus abdominis
Internal oblique
Transversalis fascia

Question 11

Floor of IC

Answer 11

Inguinal ligament + lacunar ligament

Question 12

Contents of the IC

Answer 12

Spermatic cord
Round ligament of uterus
Ilioinguinal nerve
Genital branch of the genitofemoral nerve

Question 13

The journey of the round ligament of the uterus

Answer 13

It originates from the uterine horn and travels through the inguinal canal to attach at the labia majora.

Question 14

Something worthy of note about the ilioinguinal nerve

Answer 14

It only travels through part of the inguinal canal, exiting via the superficial inguinal ring (it does not pass through the deep inguinal ring)

Question 15

Nerve at most risk of damage during inguinal hernia repair

Answer 15

Ilioinguinal nerve

Question 16

What is the pampiniform plexus?

Answer 16

A network of veins, responsible for the venous drainage of the testes. It has a unique configuration, wrapping itself around the testicular artery

Question 17

Mid-inguinal point

Answer 17

Halfway between the pubic symphysis and the anterior superior iliac spine. The femoral pulse can be palpated here.

Question 18

Midpoint of the inguinal ligament

Answer 18

Halfway between the pubic tubercle and the anterior superior iliac spine (the two attachments of the inguinal ligament). The opening to the inguinal canal is located just above this point.

Question 19

Deep inguinal ring location

Answer 19

Found above the midpoint of the inguinal ligament, lateral to the epigastric vessels.

Question 20

What forms the deep inguinal ring?

Answer 20

The ring is created by the transversalis fascia, which invaginates to form a covering of the contents of the inguinal canal.

Question 21

Superficial ring location

Answer 21

The superficial (external) ring marks the end of the inguinal canal, and lies just superior to the pubic tubercle.

Question 22

What forms the superficial inguinal ring?

Answer 22

It is a triangle shaped opening, formed by the evagination of the external oblique, which forms another covering of the inguinal canal contents.

Question 23

What prevents the superficial ring from widening?

Answer 23

This opening contains intercrural fibres, which run perpendicular to the aponeurosis of the external oblique and prevent the ring from widening.

Question 24

What is a hernia?

Answer 24

A hernia is defined as the protrusion of an organ or fascia through the wall of a cavity that normally contains it.

Question 25

What is an indirect hernia?

Answer 25

The peritoneal sac enters the inguinal canal through the deep inguinal ring.

Question 26

Cause of indirect hernia

Answer 26

They are caused by the failure of the processus vaginalis to regress.

Question 27

Indirect hernia process

Answer 27

The peritoneal sac (and potentially loops of bowel) enters the inguinal canal via the deep inguinal ring. The degree to which the sac herniates depends on the amount of processus vaginalis still present. It can reach the scrotum

Question 28

Cause of direct inguinal hernia

Answer 28

Direct inguinal hernias are acquired, usually in adulthood, due to weakening in the abdominal musculature.

Question 29

Direct hernia process

Answer 29

The peritoneal sac bulges into the inguinal canal via the posterior wall medial to the epigastric vessels and can enter the superficial inguinal ring. The sac is not covered with the coverings of the contents of the canal.

Question 30

Types of hernia based on the location of the epigastric vessels

Answer 30

Indirect - Lateral

Direct - Medial

Question 31

Epigastric hernia

Answer 31

Between umbilicus and ASIS, caused by weakness in rectus sheath

Question 32

Paraumbilical hernia

Answer 32

Congenital umbilical hernia causing protruding umbilicus

Question 33

Incisional hernias

Answer 33

Occurs after surgery

Question 34

Parts of a hernia

Answer 34

Neck, Body

Question 35

Contents of a hernia

Answer 35

Omentum 
Coils of small intestine
Appendix (right side)
Sigmoid colon (left side)
Part of urinary bladder 
Peritoneal fluid 
Caecum

Question 36

What type of inguinal hernia is more painful?

Answer 36

Indirect, due to narrow neck and compromised blood supply. It can become incarcerated, unable to return or obstructed