diaphragm embryology Flashcards
what type of septum is the diaphragm ? and its function ?
dome shaped, musculo-tendinous septum
separates thoracic cavity from abdominal cavity & primary muscle of respiration
several opening of the diaphragm and their associated levels ?
- caval opening/hiatus (vena caval foramen) , IVC - T8
- oesophageal hiatus - T10
- aortic hiatus - T12
4 structures that diaphragm is derived from ?
- septum transversum - central tendon
- pleuroperitoneal membrane - muscular part
- peripheral margin - peripheral muscular part
- dorsal esophageal mesentery - crura of diaphragm
what gives rise to the crura of the diaphragm ?
mesentery of the oesophagus
what is the crura ?
stout(fat) columns of muscle tissue that anchor the diaphragm to the lumbar vertebral column posteriorly
which hiatus is within the following ?
1. right crus of diaphragm
2. right and left crura of diaphragm
- oesophageal
- (abdominal) aortic
what happens week 4-5 in development of diaphragm ?
- Septum transversum grows and forms “pericardio-peritoneal” diaphragm
- Diaphragm descends from C3-C5 towards thorax
- Phrenic nerve descends along with the diaphragm
what happens week 5-8 in development of diaphragm ?
- Pleuroperitoneal membranes close and form “pleuro-peritoneal” diaphragm
- Diaphragm descends to L1
what happens week 9-12 in development of diaphragm ?
- Lateral body wall mesenchyme forms additional rim around “pleuro-peritoneal” diaphragm
- This peripheral rim derives innervation from lower intercostal nerves
the septum transversum begins to condense from .1… during week ..2.. of development
- mesoderm
- 3
Where does the septum transversum :
1. appear ?
2. is innervated by ?
- in cervical region
- cervical spinal nerves
Why does the phrenic nerve (C3-5) supply the diaphragm ?
as the embryo folds during week 4, the septum transversum is displaced caudally in the embryo but carries its original nerve supply with it
What are at the sides of the septum transversum ? what do they do ?
pericardioperitoneal canals - connect the developing thoracic cavity with the developing peritoneal cavity
what later closes the pericardioperitoneal canals ?
growth of the pleuroperitoneal membranes
between weeks 5 and 7 what happens resulting in the closing of the pericardioperitoneal canals ?
pair of horizonal pleuroperitoneal membranes grow from the posterior body wall to meet the septum transversum
by week 7 what has happened for the development of the diaphragm ?
the pleuroperitoneal membranes have closed the pericardioperitoneal canals effectively separating the thoracic cavity from the abdominal cavity
By the ..1.. of development , ..2.. from the body wall have ..3… the diagphragm to complete its …4.. development
- 4th month
- myoblasts
- grown into
- muscular
name an abnormalitiy associated with development of diaphragm
congenital diaphragmatic hernia (CDH)
congenital diaphragmatic hernia (CDH) = defect of the diaphragm that …?
allows passage of abdominal viscera into the thorax
what is the most common congenital diaphragmatic hernias ?
posterolateral or bochdalek hernia or pleuroperitoneal
what does posterolateral or bochdalek hernia or pleuroperitoneal result from ?
all 3 refer to same thing of CDH
failure of the pleuroperitoneal membranes to develop and close the pericardioperitoneal canals
what are the 2 main complications and causes of mortality of congenital diaphragmatic hernia ?
- pulmonary hypoplasia
- pulmonary hypertension
Treatment of CDH in utero ?
fetoscopic endoluminal tracheal occlusion (FETO)
what is FETO as a treatment for CDH ?
fetoscopic endoluminal tracheal occlusion (FETO)
- blocking of trachea to stop fluid produced by foetal lungs escape into the amniotic fluid
- lung fluid expands the lungs, stimulates their growth, pushes abdominal contents out of chest into abdomen
