GS: Diaphragm Flashcards
What is the diaphragm?
sheet of muscle and tendon that separates the thorax from the abdomen
What is the main function of the diaphragm?
respiration
What does the diaphragm act as the most superior border of?
abdomen
Where does the diaphragm develop?
in the neck mainly from septum transversym close to the thoracic inlet
What is the nerve supply of the diaphragm?
anterior rami of C3, C4, C5 (phrenic nerve)
What are the other embrological components of the diaphragm?
- pleuroperitoneal membranes
- dorsal mesentery of the oesophagus
- ingrowth from the body wall
What are the 4 sources of origin of the diaphragm?
- spetum transversum
- 2 pleuro-perioneal folds or membranes that fuse with septum transversum and close the pericardio-peritoneal canals
- Oesophagus and its mesentery in the midline dorsally
- ingrowth from the body wall
Describe the structure of the diaphragm
originate from the xiphoid process, then the costal margin, ribs 11 and 12, then posteriorly and medial arcuate ligaments (thickenings of thoracolumbar and psoas fascia respectively)
Where do the fibres of the diaphragm converge?
central tendon
What does the diaphragm have posteriorly?
strong, muscular left and right crura
Left = L1 and L2
Right = L1, L2 and L3
Where does the median arcuate ligament lie?
midline, netween the left and right crus at the level of T12
What do the fibres of the right crus do?
cross over the midline to the left to form a loop or a sling around the oesophagus
What is the inferior surface of the diaphragm lined by?
peritoneum apart from the ‘bare area’ which is posterior to part of the liver
How does the peritoneal of the liver interact with the diaphragm?
O n the superior surface ofthe liver the peritoneum reflects on to the diaphragm to create narrow subphrenic intraperitoneal (potential) spaces where fluids can collect from the abdomen.
Describe the opening at T8
At the level of T8 (through the central tendon)
- Pasing down into the abdomen – Right phrenic nerve
- Passing up out of the abdomen– Inferior vena cava
Describe the opening at T10
At the levek of T10 (through the right crus, but left of the midline)
- Passing out of the abdomen - left gastric artery from the coeliac artery
- Passing into the abdomen - oesophgaus, anterior and posterior vagal trunks, left gastric vein
Describe the opening at T12
At the level of T12 (through the median arcuate ligament)
- passing out of the adbomen - thoracic duct, azygos and hemi azygos veins
- Passing into the abdomen - descending thoracic aorta
Describe the condition hiatus hernia
small aprt of the stomach herniates through the diaphragm into the thorax
What are the two types of hiatus hernia?
sliding and rolling
What occurs in a sliding hiatus hernia?
intra-abdominal part of the GO junction has managed to get above the diaphragmatic oesophgeal hiatus formed by the left and right crura, but mainly the right crus
What are the main symptoms experienced due to hiatus hernai?
severe heartburn and dysphagia
may be made worse after eating food or lying down
Why is the pain of sliding hiatus hernia worse after eating food?
- Normally all the acid secreting parts of the stomach are below the oesophgeal opening
- Cardia is above constrictions allowing acid to be secreted into the lower oesophagus
- Food and fluid in stomach = gastric acid release
- Irritates the lower oesophagus; increase in pain and discomfort
What occurs in a rolling hiatus hernia?
part of the fundus of the stomach has herniated through the diaphragm but the gastro-oesophageal junction is still intact below the diaphragm
How does a rolling hiatus hernia usually present?
dysphagis from compression of the oesophgeus, or early satiety, and in some cases inability to hold solid foods at all
What is a congenital diaphragmatic heria?
found in newborn babies due to incomplete development of the diaphragm
A large amount of midgut can structures can pass into the thorax. (most commonly the left side)
What is the impact of a diaphramatic hernia?
impair lung function and sometimes development
babies present with cyanosis and respiratory distress soon after birth
Where is irritation of the diaphragm referred to?
C4; shoulder tip
Brain cannot localise visceral pain
