GB 19. Diaphragm, Posterior Abdominal Wall

Question 1

Why is diaphragm a musculotendinous septum?

Answer 1

It is a musculotendinous septum as there is both a muscular part and a tendinous part.
- it has a central tendon

Question 2

Where are the 2 crus located in the abdomen? What is it attached to?

Answer 2

Right Crus:
- attached to L1, L2 + L3 vertebrae

Left Crus:
- attached to L1 + L2 vertebrae

Question 3

What are the 3 different crura/ligaments?

Answer 3

[1] Median Arcuate Ligament (across aorta)
[2] Medial Arcuate Ligament (psoas fascia)
[3] Lateral Arcuate Ligament (quadratus fascia)

Question 4

Which crura/ligament does the aorta come through/pass behind?

Answer 4

Median Arcuate Ligament

Question 5

How many domes is the diaphragm made up of?

Answer 5

Right Dome + Left Dome

Question 6

Which nerve supplies the diaphragm?

Answer 6

Phrenic Nerve

• roots C3, C4 and C5
• “3, 4, 5 KEEPS THE DIAPHRAGM ALIVE”

Question 7

What is the main blood/arterial supply to the diaphragm?

Answer 7

Inferior Phrenic Artery

Question 8

At which level does the aorta enter through the diaphragm?

Answer 8

T12

Question 9

At which level does the esophagus enter through the diaphragm?

Answer 9

T10

Question 10

At which level does the Inferior Vena Cava enter/exit through the diaphragm?

Answer 10

T8

Question 11

Which type of tissue of is the Inferior Vena Cava located in?

Answer 11

Located in the Central Tendon

- the central tendon does not move so it always keeps the IVC open

Question 12

Which type of tissue is the esophagus located in? What tissues/tendons surround the esophagus?

Answer 12

The right crus gives tendons (fibres) that goes around the esophagus
- this is more flexible so it allows for the esophagus to open and close

Question 13

What structures open through the diaphragm at the level of T8?

Answer 13

• Inferior Vena Cava

- Right Phrenic Nerve

Question 14

What structures open through the diaphragm at the level of T10?

Answer 14

• Esophagus

- Vagi Nerves

Question 15

What structures open through the diaphragm at the level of T12?

Answer 15

• Aorta
• Thoracic Duct
• Azygous Vein

Question 16

Why is the left dome of the diaphragm higher than the right dome of the diaphragm?

Answer 16

left dome is slightly higher than the right dome because of liver

Question 17

If there is an injury in the diaphragm, where is pain referred to?

Answer 17

Pain referred to shoulder (C4)

Question 18

What is a diaphragmatic hernia? What are some causes of a diaphragmatic hernia?

Answer 18

It is when there is an abnormal opening in the diaphragm

[1] Traumatic
[2] Embryological

Question 19

What is a hiatus hernia? What are the 2 types of hiatus hernia and what is the difference?

Answer 19

Hiatus Hernia:

[1] SLIDING Hernia
[2] ROLLING Para-Esophageal Hernia

Question 20

Where does the abdominal aorta enter the abdomen and at which vertebral level does it end?

Answer 20

• it enters the abdomen behind the median arcuate ligament

- it ends at the vertebral level of L4 (this is where it divides into common iliac)

Question 21

What are the 4 unpaired branches of the abdominal aorta?

Answer 21

[1] T12 Coeliac Trunk
[2] L1 Superior Mesenteric
[3] L3 Inferior Mesenteric
[4] L4 Median Sacral

Question 22

What are the 4 paired branches of the abdominal aorta?

Answer 22

[1] Inferior Phrenic at T12
[2] Middle Adrenal at L1
[3] Renal at L2
[4] Gonadal at L2

Question 23

What does the 444 mean in the abdominal aorta?

Answer 23

• 4 unpaired branches
• 4 paired branches
• 4 pairs of lumbar arteries
• common iliac arteries @ L4

Question 24

What are the lymph nodes in the posterior abdominal wall?

Answer 24

[1] Iliac Nodes
[2] Pre-Aortic Nodes
[3] Common Iliac Nodes
[4] Inferior Mesenteric Nodes
[5] Superior Mesenteric Nodes

Question 25

What are the 2 main lymph drainage ducts?

Answer 25

[1] Thoracic Duct
- thoracic duct drains into where the left subclavian and left internal jugular meet
[2] Right Lymphatic Duct
- right drains into right subclavian and right internal jugular

Question 26

What passes through the medial arcuate ligaments?

Answer 26

sympathetic trunks

Question 27

What passes through the lateral arcuate ligaments?

Answer 27

subcostal nerve

Question 28

What passes through the crura?

Answer 28

splanchnic nerves

Question 29

What does the Lumbar Plexus consist of? What are the nerves involved and what ar ethe muscles they pass through?

Answer 29

[1] Lateral to Psoas Major (from lateral to medial)

(a) Subcostal Nerve (T12)
(b) Iliohypogastric Nerve
(c) Ilioinguinal Nerve
(d) Lateral Cutaneous Nerve of Thigh
(e) Femoral Nerve

[2] through Psoas Major
(a) Genitofemoral Nerve

[3] Medial to Psoas Major

(a) Obturator Nerve
(b) (Lumbosacral Trunk)

Question 30

What are the main branches of the Sacral Plexus?

Answer 30

[1] Sciatic Nerve
[2] Pudendal Nerve
- nerve to the perineum
- supplies sphincters 
[3] Superior Gluteal Nerves
[4] Inferior Gluteal Nerves
[5] Pelvic Splanchnic Nerves

Question 31

What is the root of the sciatic nerve?

Answer 31

L4 to S3

Question 32

What does the sciatic nerve branch into?

Answer 32

[1] Tibial Nerve (L4 to S3 - anterior division)

[2] Common Peroneal Nerve (L4 to S2 - posterior division)

Question 33

What are the nerve roots for the pelvic splanchnic nerves?

Answer 33

S2, S3 + S4

- they are parasympathethic nerves