2. Inguinal Canal (Brauer)

Question 1

What two nerves serve the posterior surface of the scrotum?

Answer 1

Posterior scrotal nerves - which come from the perineal branch of the pudendal nerve

Perineal branches of the posterior cutaneous nerve of the thigh

Question 2

Which opening will gut contents pass through in a direct hernia?

Answer 2

The superficial inguinal ring (not the deep inguinal ring).

Question 3

What are the boundaries of the inguinal triangle?

Answer 3

Inferior epigastric vessels

Rectus abdominis

Inguinal ligament

Question 4

What two nerves serve the anterior portion of the scrotum?

Answer 4

Anterior scrotal nerves – which come from the illioinguinal nerve

Genital branch of the genitofemoral nerve

Question 5

What innervates the dartos smooth muscle?

Answer 5

Sympathetic branch of the autonomic nervous system

Question 6

To which lymph nodes does the lymph of the testis drain?

Answer 6

The lumbar nodes – a.k.a. caval/aortic

Question 7

Where does the conjoint tendon insert?

Answer 7

The conjoint tendon inserts on the pectineal line.

Question 8

What gives rise to the lacunar ligament?

Where does the lacunar ligament attach?

Answer 8

The lacunar ligament arises from fibers of the inguinal ligament.

The lacunar ligament attaches to the pubic tubercle.

Question 9

What are the two sources of blood supply to the scrotum?

Answer 9

Anterior: anterior scrotal branches coming from the deep external pudendal artery

Posterior: posterior scrotal branches coming from the perineal artery (a branch of the pudendal)

Question 10

What embryonic layer forms the testes and ovaries?

Answer 10

Intermediate mesoderm

Question 11

To which lymph nodes does the lymph of the scrotum drain?

Answer 11

The superficial inguinal nodes

Question 12

What layers of the testicle are given rise to by the internal oblique?

Answer 12

The cremasteric fascia and cremaster muscle

Question 13

What abdominal layer gives rise to the internal spermatic fascia?

Answer 13

The transversalis fascia

Question 14

What layers of the abdominal wall will cover gut contents in an indirect hernia?

Answer 14

Same as cover the spermatic cord (transversalis fascia, internal oblique aponeurosis, external oblique aponeurosis, dartos fascia)

Question 15

From what other structures does the cremaster muscle originate?

Answer 15

Fibers from the internal oblique muscle.

Question 16

What forms the roof of the deep inguinal ring, middle third of the inguinal canal, and superficial inguinal ring?

Answer 16

The roof of the deep inguinal ring is transversalis fascia.

The roof of the middle third of the inguinal canal are the internal oblique and transverse abdominal muscles/aponeuroses.

The roof of the superficial inguinal ring is the medial crus of the aponeurosis of the external oblique

Question 17

What appears to be the purpose of the pampiniform plexus?

Answer 17

Thermal regulation

Question 18

Where do we see direct inguinal hernias?

Where do we see indirect inguinal hernias?

Answer 18

Direct inguinal hernias are found in the inguinal triangle (Hesselbach’s triangle) – medial to the inferior epigastric arteries.

Indirect inguinal hernias are found lateral to the inguinal triangle – lateral to the inferior epigastric arteries.

Question 19

Why do 40% of femoral hernias present with strangulation?

Answer 19

Because of the strength of the lacunar ligament just medial to the femoral ring.

Question 20

What is the conjoint tendon?

Answer 20

The combined aponeuroses of the internal oblique and transversus abdominis muscles.

Question 21

What gives rise to the pectineal ligament?

Where is the pectineal ligament attach?

Answer 21

The pectineal ligament is given rise to by fibers of the lacunar ligament, which themselves come from the inguinal ligament.

The pectineal ligament attaches to the pectineal line.

Question 22

What gives rise to the intercrural fibers of the inguinal ligament?

Answer 22

The aponeurosis of the external oblique on the contralateral side reaching over to reinforce the parallel fibers.

Question 23

What layers of the abdominal wall will cover the gut contents in a direct hernia?

Answer 23

Transversalis fascia, peritoneum, and skin.

Question 24

What innervates the cremaster muscle?

Answer 24

The genital branch of the genitofemoral nerve

Question 25

Describe the path of the testicles through the abdominal layers and into the scrotum

Answer 25

Testicle grabs a piece of the peritoneum, then passes through and grabs the transversalis fascia, passes through (but does not grab) the transversus abdominis, passes through and grabs the internal oblique muscle, passes through and grabs the external oblique muscle, passes through and grabs Scarpa’s fascia, and enters a pocket of skin which forms the scrotum.

Question 26

What gives rise to the iliopubic tract?

Where do we find the iliopubic tract?

Answer 26

Transversalis fascia.

Paralleling, but deep to, the inguinal ligament.

Question 27

What forms the posterior wall of the deep inguinal ring, middle third of the inguinal canal, and superficial ring?

Answer 27

Transversalis fascia forms the posterior wall of the deep inguinal ring and middle third of the inguinal canal.

The posterior wall of the superficial ring is the conjoint tendon, as well as the reflected inguinal ligament.

Question 28

What abdominal layer gives rise to the external spermatic fascia?

Answer 28

External oblique

Question 29

To what does the lateral crus attach?

Answer 29

The pubic tubercle.

Question 30

To what does the medial crus attach?

Answer 30

The pubic crest

Question 31

What abdominal layers give rise to the scrotum?

Answer 31

Skin and Scarpa’s fascia (becoming Dartos fascia in the scrotum).

Question 32

Where do the gonadal arteries come from?

Answer 32

The aorta on the right – and the left renal artery on the left.

Question 33

What abdominal layer gives rise to the cremasteric fascia and cremaster muscle?

Answer 33

The internal oblique

Question 34

Which nerve passes through the superficial inguinal ring, but does not pass through the deep inguinal ring?

Answer 34

The illioinguinal nerve

Question 35

What is a vericocele?

Where does it usually occur, and why?

Answer 35

A fullness of the scrotum, variable in size, due to a backing up of blood into the pampiniform plexus of the testicle.

Usually occurs in the left scrotum, because the pampiniform plexus of the left scrotum drains into the left renal artery – which can become compressed.

Question 36

What vessel gives rise to the cremasteric artery?

Answer 36

The inferior epigastric artery

Question 37

What forms of the anterior wall of the deep inguinal ring, middle third of the inguinal canal, and superficial ring?

Answer 37

The anterior wall of the deep inguinal ring is formed by the lateral crus of the aponeurosis of the external oblique and the aponeurosis of the internal oblique.

The anterior wall of the middle third of the inguinal ligament is formed by the lateral crus and intercrural fibers of the external oblique.

The anterior wall of the superficial inguinal ring is formed by the aponeurosis of the external oblique, which continues onto the spermatic cord as external spermatic fascia.

Question 38

What testicular layer is given rise to by the peritoneum?

Answer 38

The tunica vaginalis (parietal and visceral)