Ch 32 Diaphragm Flashcards
Emrbyologically, the diaphragm is formed by
- Septum transversum (ventrally)
- foregut mesentery and 2 pleuroperitoneal folds (dorsally)
Movement of the diaphragm provides approximately ___ % of the change in intrathoracic volume during quiet respiration, and the ____ provide the rest.
- 75
- intercostal muscles
Lymph flow is unidirectional/bidirectional. What is the final destination of lymph?
unidirectional
thoracic trunks
Parts of the diaphragm
Tendinous centre
3 thin peripheral muscles:
- pars lumbalis (R and L crura)
- pars costalis
- pars sternalis
Where do the crura of pars lumbalis attach?
L3 body / L4 cranioventral border
Which part of the diaphragm attaches to L3/L4?
Pars lumbalis crura
Where does pars costalis of the diaphragm attach?
8-13th rib
Where does pars sternalis of the diaphragm attach?
xiphoid process cartilage
From dorsal to ventral, what are the openings in the diaphragm?
aortic hiatus
esophageal hiatus
caudal vena cava foramen
what passes through the aortic hiatus?
aorta
azygos
hemiazygos veins
lumbar cistern of thoracic duct
what passes through the esophageal hiatus?
esophagus
vagus nerve trunks
what passes through the vena cava foramen?
caudal vena cava
Where is the caudal vena cava foramen located?
at the junction of the muscular and tendinous portion of the diaphragm
Which 2 recesses does the diaphragm form?
phrenicocostalis
phrenicolumbalis
DV or VD?
VD
DV or VD ?
DV
LL or RL?
LL
LL or RL?
RL
What / where is the intercrural cleft?
- a shorter convex, opaque line caudal and ventral to the crura
In which recumbency are the crura parallel?
RL
In which recumbency are the crura crossed?
LL
What do the crura do in RL and LL?
RL: parallel
LL: crossed (sometimes)
What can be a cause of the appearance of the crura to be extensively separated (by up to 2.5 vertebral lengths)?
- rotation of the patient
- XR beam centre over cranial or mid thorax
What can be used to distinguish RL from LL?
confluence of the CVC with the right crus of the diaphragm
- in RL this will be the cranial crus
When is a single domed diaphragm seen on a VD?
when XR beam is centred over mid-abdo
When is a single domed diaphragm seen on a DV?
when XR beam is centred over mid-thorax
When is a 3-domed diaphragm seen on a VD?
when XR beam is centred over mid-thorax
When is a 3-domed diaphragm seen on a DV?
when XR beam is centred over mid-abdo
What is the normal intersection point of the diaphragm and the spine, and what is the normal variation?
(T9-)T11 - T13 (-L1)
How many vertebral lengths does normal respiration affect the diaphragm position?
1/2 - 2
In cats, the diaphragmatic crura change position equally on different projection, as with dogs. True or False?
False; variation is much smaller and distinction of diaphragmatic anatomy is more challenging (probably too small?).
RL or LL (cat)?
LL
RL or LL (cat)?
RL
2 causes of a more convex and cranially extending diaphragm?
2 causes of an asymmetric diaphragmatic shape
- unilateral tension pneumothorax
- hemiparalysis
Which way (cranial / caudal) will the diaphragm shift with a generalised paralysis?
Cranial
2 causes of bilateral caudal displacement of the diaphragm
- Severe respiratory disease
- Bilateral tension pneumothorax