Diaphragm

Question 1

What is the diaphragm?

Answer 1

Sheet of muscle and tendon which separates thorax from the abdomen

Question 2

What is the main function of the diaphragm?

Answer 2

Respiratory, responsible for inspiration at rest

Question 3

What borders of the abdomen is the diaphragm a part of ?

Answer 3

Superior Border

Upper Posterior Abdominal Wall

Question 4

Where does the diaphragm develop embryologically and what nerve supply does it pick up here?

Answer 4

Develops in the neck from the septum transverse close to the thoracic inlet

Relieves the ventral rami of C3, 4, 5 (phrenic nerve)

Question 5

How does the diaphragm have a nerve supply from the cervical ventral rami despite having an adult position in the base of the thorax?

Answer 5

As the lungs expand they force the diaphragm inferiorly through the thoracic cage and the diaphragm drags its nerve supply inferiorly

Question 6

What are the 4 embryological sources of origin of the diaphragm?

Answer 6

Septum Transversum
2x Pleuro-peritoneal Folds
Oesophagus and Mesentery
Ingrowth of body wall

Question 7

Where does the left and right crura originate from?

Answer 7

Left: L1, L2
Right: L1, 2, 3

Question 8

Where does the median arcuate ligament lie?

Answer 8

Lies in the midline, between the muscular crura at the level of T12

Question 9

What is the inferior surface of the abdomen lined with and where is the bare area?

Answer 9

Lined by peritoneum

Except the bare area which is just posterior to part of the liver

Question 10

T8 opening of the diaphragm?

Answer 10

Through central tendon

Right phrenic nerve
IVC

Question 11

T10 opening of the diaphragm?

Answer 11

Through right crus but left of midline

Left Gastric Vessels
Oesophagus
Ant, Post Vagal Trunks

Question 12

T12 opening of the diaphragm?

Answer 12

Behind median arcuate ligament

Thoracic duct
Azygos veins
Thoracic aorta

Question 13

What is a hiatus hernia?

Answer 13

When small part of the stomach herniates through the diaphragm and into the thorax

Question 14

What is a sliding hiatus hernia?

Answer 14

Usually when an intraperitoneal part of the gastro-oesophageal junction herniates above the diaphragmatic oesophageal hiatus

Question 15

What is a rolling hiatus hernia?

Answer 15

When the fundus of the stomach has herniated through the diaphragm but the gastro-oesophageal reflex remains intact and below the diaphragm

Question 16

Which group are normally affected by diaphragmatic hernias and how do these occur?

Answer 16

Babies

Due to incomplete development of the diaphragm

Question 17

How often to diaphragmatic hernias occur?

Answer 17

1 in 4000 live births

Question 18

What structures tend to pass through a diaphragmatic hernia, on what side is most common and what is the result of this?

Answer 18

Midgut structures can pass through the thorax

Usually on left side

Result can be impaired lung function and in some cases affect lung development

Question 19

When do babies present with diaphragmatic hernia and what 2 things do they present with first?

Answer 19

Usually after birth

Cyanosis and respiratory distress

Question 20

How could you differentiate between pain from a bleeding duodenal ulcer and someone having a MI?

Answer 20

Both cause sympathetic response to compensate for ischaemia leading to:

• tachycardia
• sweating
• pallor

MI tends to be more painful central chest pain that radiates to left arm

DU will have altered blood in stool (malaena)

Question 21

Why is pericardial or diaphragmatic pain referred to shoulder tip?

Answer 21

Both diaphragm and pericardium are supplied by phrenic nerve - C3, 4, 5

Brain cannot localise visceral pain and thinks it is coming from the skin.
C4 dermatome is over the shoulder tip.