Anterior Abdominal Wall and Inguinal Anatomy

Question 1

Where do the inferior epigastric artery and vein run in relation to the anterior abdominal wall?

Answer 1

In the posterior rectus sheath

Question 2

What is McBurney’s point?

Answer 2

This is located a 1/3 of the way between the ASIS and the umbilicus and this is where you would find the appendix

Question 3

What is the arcuate line?

Answer 3

Horizontal line that demarcates the lower limit of the posterior layer of the rectus sheath. It is also where the inferior epigastric vessels perforate the rectus abdominis.

Question 4

Describe the order of the anterior abdominal wall muscles from superficial to deep

Answer 4

External oblique, internal oblique, transversalis muscle and the rectus abdominis muscle lies in the middle in the rectus sheath and transversalis fascia

Question 5

Describe the external oblique muscle

Answer 5

Attaches to the iliac crest and ASIS and then to the pubic tubercle as well as the xipohoid process superiorly. It’s the most superficial muscle and it’s fibres go ‘into your front pockets’, and the free border also forms the inguinal ligament

Question 6

Describe the external oblique muscle

Answer 6

Attaches to the iliac crest and ASIS and then to the pubic tubercle as well as the xipohoid process superiorly. It’s the most superficial muscle and it’s fibres go ‘into your front pockets’, and the free border also forms the inguinal ligament

Question 7

The free border of which abdominal muscle gives rise to the inguinal ligament?

Answer 7

External oblique

Question 8

Describe the internal oblique muscle

Answer 8

Attaches to the iliac crest, ASIS and the pubic tubercle and contributes to the formation of the conjoint tendon

Question 9

Which two abdominal muscles contribute to the conjoint tendon?

Answer 9

Transverse abdominis and internal oblique

Question 10

Describe the transverse abdominis muscle

Answer 10

Attaches to the iliac crest, ASIS and the pubic tubercle where it contributes to the conjoint tendon (alongside internal oblique), and below the muscle it gives off the transversalis fascia

Question 11

What is the function of the transversalis fascia?

Answer 11

To separate the muscles from the parietal peritoneum

Question 12

What is the function of the transversalis fascia?

Answer 12

To separate the muscles from the parietal peritoneum

Question 13

Describe the rectus abdominis muscle

Answer 13

This muscle lies within the rectus sheets and has tendinous intersections and provides the arcuate line where the posterior border of the rectus sheath ends.

Question 14

Describe the inguinal ligament

Answer 14

It is formed by the lower edge (aponeurosis) of the external oblique and extends from ASIS to pubic tubercle

Question 15

Describe the inguinal canal

Answer 15

The inguinal canal is a narrow passage that lies superior and parallel to the medial half of the inguinal ligament and it runs medially and inferiorly towards the testes and extends from the deep inguinal to the superficial inguinal ring.

Question 16

What is the deep inguinal ring?

Answer 16

It’s an opening in the transversalis fascia (just above the mid-inguinal point)

Question 17

What is the superficial inguinal ring?

Answer 17

A triangular opening in the external oblique aponeurosis which is superior and lateral to the pubic tubercle

Question 18

What structures pass through the deep inguinal ring?

Answer 18

The spermatic cord (male)/round ligament (female) and the genitofemoral nerve in order to enter the inguinal canal

Question 19

How does the ilioinguinal nerve enter the inguinal canal?

Answer 19

It doesn’t enter via the deep inguinal ring, it instead pierces the transversalis fascia to enter

Question 20

How does the ilioinguinal nerve enter the inguinal canal?

Answer 20

It doesn’t enter via the deep inguinal ring, it instead pierces the transversalis fascia to enter

Question 21

Describe the layers of the spermatic cord

Answer 21

The spermatic cord has the ductus deferens (DD) running centrally, with the artery of the DD running on top of this structure. Surrounding the DD is the testicular artery (with pampniform venous plexus), lymph vessels and autonomic nerve fibres incased in the internal spermatic fascia. Above the internal spermatic fascia is the cremasteric muscle and fascia with the genital branch of the genitofemoral nerve on top, and the is surrounded by the external spermatic fascia

Question 22

Describe the layers of the spermatic cord

Answer 22

The spermatic cord has the ductus deferens (DD) running centrally, with the artery of the DD running on top of this structure. Surrounding the DD is the testicular artery (with pampniform venous plexus), lymph vessels and autonomic nerve fibres incased in the internal spermatic fascia. Above the internal spermatic fascia is the cremasteric muscle and fascia with the genital branch of the genitofemoral nerve on top, and the is surrounded by the external spermatic fascia and the ilioinguinal nerve runs on top

Question 23

Outline the layers of the scrotum from deep to superficial

Answer 23

Testis, visceral tunica vaginalis, parietal vaginalis, internal spermatic fascia, cremaster muscle, external spermatic fascia and then dartos

Question 24

Outline the origins of the layers of the spermatic cord

Answer 24

Internal spermatic fascia - this is from the transversalis fascia
Cremaster muscle and fascia - from the internal oblique muscle
External spermatic fascia - from the external oblique aponeurosis
Dartos muscle - from the superficial (scarpas) fascia

Question 25

What is the function of the dartos muscle in males?

Answer 25

It’s a smooth muscle that is involved in temperature regulation of the testes

Question 26

What is the function of the cremaster muscle in males?

Answer 26

This is a somatic muscle involved in retracting the testes and is supplied by the genitofemoral nerve (genital part is motor, femoral part is sensory to skin on the inner thigh)

Question 27

What is a hernia?

Answer 27

An abnormal weakness/hole in an anatomical structure which allows something to protrude through

Question 28

What are the causes of herniation?

Answer 28

Anything that increases intra-abdominal pressure e.g. straining, chronic lung disease, obesity and heavy lifting

Question 29

Describe an inguinal hernia

Answer 29

This hernia occurs where there is protrusion of a structure such as the bowel through the inguinal canal for a variable distance, which subsequently exits through the superficial inguinal ring

Question 30

What is an indirect inguinal hernia?

Answer 30

Where there is a protrusion through the deep inguinal ring and into the inguinal canal, and out of the superficial inguinal ring

Question 31

What is a direct inguinal hernia?

Answer 31

When a protrusion enters the inguinal canal medial to the deep inguinal ring (in the inguinal/Hesselbach’s triangle) directly

Question 32

What are the types of indirect inguinal hernia?

Answer 32

Congenital and acquired

Question 33

Describe the common causes of congenital indirect inguinal hernias

Answer 33

This form of hernia often occurs secondary to patent processes vaginalis and therefore the protrusion follows the pathway which the testes made during their pre-birth development

Question 34

Describe acquired indirect inguinal hernias

Answer 34

These kinds of hernia can pass through the entire length of the inguinal canal in the spermatic cord and display in the scrotum, which is rarely seen in direct hernias.

Question 35

What is the inguinal/ Hesselbach’s triangle?

Answer 35

This area is bound by the inferior epigastric artery superiorly, the inguinal ligament inferiorly and the lateral border of rectus abdominis medially.

Question 36

What is the femoral canal?

Answer 36

This is the way that the femoral artery, vein and nerve leave the abdominal cavity to enter the thigh

Question 37

What is the cause of umbilical herniation?

Answer 37

These are common and are often present at birth; they are caused by incomplete closure of the abdominal cavity prior to birth

Question 38

How do you locate the mid-inguinal point and what is it’s significance?

Answer 38

Half-way between the pubic sum-his and ASIS, and this is the position of the femoral artery (and therefore the site of the femoral pulse)

Question 39

How would you locate the superficial inguinal ring on surface anatomy?

Answer 39

It is just medial to the pubic tubercle

Question 40

How would you locate the deep inguinal ring on surface anatomy?

Answer 40

DIR is in the midpoint between the ASIS and pubic tubercle