Inguinal canal

Question 1

Development of the inguinal canal:

Answer 1

In males:
Formation of the inguinal canal occurs concurrently with testicular descent prior to birth At Week 7: Testes located within the abdominal cavity, but retroperitoneally (Lies behind peritoneum)
Females:
Ovaries (except in rare cases) do not enter the inguinal canal

Week 7 (cont.):
* Caudal genital ligament attaches to superior pole of testes
* Gubernaculum (mesenchyme) anchors the inferior pole to scrotal swelling
Week 12:
* Peritoneum forms an evagination, the vaginal process, as it grows towards the scrotal swelling
* Vaginal process creates a cavity as it pushes through the abdominal layers, giving rise to the inguinal canal
9 Months:
* Testes reached scrotal sac, therefore now external
* Caudal genital ligament regresses, but gubernaculum still anchors the testes
* Therefore the gubernaculum directs the migration of the testes
* Shortening of the gubernaculum and increased size of abdominal organs promote descent as intra-abdominal pressure increases forcing the testes through the canal.

Question 2

Question 3

Transversalis fascia:

Answer 3

1st layer of anterior abdominal wall encountered by the process vaginalis in the gubernaculum. Part of the transversalis fascia is stretched and pushed ahead of the process vaginalis towards the labia scrotal swelling
Transversalis fascia will become the internal spermatic fascia of the spermatic cord and the outpouching of the transversalis fascia will create the deep inguinal ring

Question 4

Internal abdominal oblique:

Answer 4

Also be drawn toward the labia scrotal swellings becoming the cremasteric muscle

Question 5

External abdominal oblique

Answer 5

Pulled along to become the external spermatic fascia and will form the superficial inguinal ring.

Question 6

Process vaginalis will pass inferior to margin of transversus abdominus muscle so this muscle will not contribute a layer to the spermatic cord

Question 7

Question 8

Inguinal canal:

Answer 8

• Channel-like passage through inferior portion of anterior abdominal wall
• Found in both sexes (♂ & ♀)
• 4cm long
• Extends from deep inguinal ring to superficial inguinal ring
• Runs obliquely, parallel & 1 finger’s breadth above medial 1⁄2 of inguinal ligament
• Serves as a pathway by which structures can pass through the abdominal wall to the external genitalia.
• Clinical NB because it is a potential weakness and site for herniation

Question 9

Inguinal canal content

Answer 9

• Ilioinguinal nerve
• Genital branch of genitofemoral nerve
• Female: round lig. Of uterus
• Male: Spermatic chord

Question 10

Boundaries of the inguinal canal is described in ______ and has two openings _____________

Answer 10

thirds:
Proximal, middle and distal third
superficial and deep rings

Question 11

Boundaries of the inguinal canal

Answer 11

Mnemonic : MALT: (2M, 2A, 2L, 2T)
1. Superior wall (roof): 2 x Muscles
* Internal oblique Muscle
* Transversus abdominis Muscle
2. Anterior wall: 2 x Aponeuroses
* Aponeurosis of external oblique
* Aponeurosis of internal oblique
3. Floor: 2 x Ligaments
* Inguinal Ligament
* Lacunar Ligament
4. Posterior wall: 2 x Ts
* Transversalis fascia
* Conjoint Tendon

Question 12

Question 13

Inguinal canal: Rings

Answer 13

• deep (internal) ring
• Superficial (external) ring:

Question 14

Deep (internal) ring:

Answer 14

• Above the midpoint of inguinal ligament
• Lateral to the epigastric vessels
• Formed by transversalis fascia

Question 15

Superficial (external) ring:

Answer 15

• Marks end of inguinal canal
• Lies superior to pubic tubercle
• Triangle shaped opening
• Formed by evagination of the external oblique
  Opening contains intercrural fibers which perpendicular to the aponeurosis of the external oblique- this is to prevent the ring from tearing and stretching and keeping the opening intact

Question 16

Question 17

Inguinal hernia:

Answer 17

Partial protrusion of the parietal peritoneum aswell as the small intestine through a normal or an abnormal opening originating from the abdominal cavity

Question 18

Indirect inguinal hernia
Features:

Answer 18

– Traverses through deep ring
– Lateral to inferior epigastric blood vessels
– Descends whole length of inguinal canal
Swelling originating lateral to the inferior epigastric vessels, goes through deep ring and proceeds to scrotum
Which results in swelling which is medial to the pubic tubercle before entering the scrotum

Question 19

Femoral hernias

Answer 19

occur in the femoral triangle and the swelling is inf. To the inguinal ligaments and lateral to the pubic tubercle

Question 20

Direct inguinal hernias:

Answer 20

• Due to weakened part of the anterior surface of the abdominal wall
• Medial to inf. Epigastric blood vessels
• Through Hasslebach’s triangle
• Bulge occurs above the inguinal ligament and medial to epigastric blood vessels

Question 21

Question 22