Diaphragm Flashcards
What is the diaphragm?
Sheet of muscle and tendon which separates thorax from the abdomen
What is the main function of the diaphragm?
Respiratory, responsible for inspiration at rest
What borders of the abdomen is the diaphragm a part of ?
Superior Border
Upper Posterior Abdominal Wall
Where does the diaphragm develop embryologically and what nerve supply does it pick up here?
Develops in the neck from the septum transverse close to the thoracic inlet
Relieves the ventral rami of C3, 4, 5 (phrenic nerve)
How does the diaphragm have a nerve supply from the cervical ventral rami despite having an adult position in the base of the thorax?
As the lungs expand they force the diaphragm inferiorly through the thoracic cage and the diaphragm drags its nerve supply inferiorly
What are the 4 embryological sources of origin of the diaphragm?
Septum Transversum
2x Pleuro-peritoneal Folds
Oesophagus and Mesentery
Ingrowth of body wall
Where does the left and right crura originate from?
Left: L1, L2
Right: L1, 2, 3
Where does the median arcuate ligament lie?
Lies in the midline, between the muscular crura at the level of T12
What is the inferior surface of the abdomen lined with and where is the bare area?
Lined by peritoneum
Except the bare area which is just posterior to part of the liver
T8 opening of the diaphragm?
Through central tendon
Right phrenic nerve
IVC
T10 opening of the diaphragm?
Through right crus but left of midline
Left Gastric Vessels
Oesophagus
Ant, Post Vagal Trunks
T12 opening of the diaphragm?
Behind median arcuate ligament
Thoracic duct
Azygos veins
Thoracic aorta
What is a hiatus hernia?
When small part of the stomach herniates through the diaphragm and into the thorax
What is a sliding hiatus hernia?
Usually when an intraperitoneal part of the gastro-oesophageal junction herniates above the diaphragmatic oesophageal hiatus
What is a rolling hiatus hernia?
When the fundus of the stomach has herniated through the diaphragm but the gastro-oesophageal reflex remains intact and below the diaphragm
Which group are normally affected by diaphragmatic hernias and how do these occur?
Babies
Due to incomplete development of the diaphragm
How often to diaphragmatic hernias occur?
1 in 4000 live births
What structures tend to pass through a diaphragmatic hernia, on what side is most common and what is the result of this?
Midgut structures can pass through the thorax
Usually on left side
Result can be impaired lung function and in some cases affect lung development
When do babies present with diaphragmatic hernia and what 2 things do they present with first?
Usually after birth
Cyanosis and respiratory distress
How could you differentiate between pain from a bleeding duodenal ulcer and someone having a MI?
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)
Why is pericardial or diaphragmatic pain referred to shoulder tip?
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.
