CH.10 The IVC Flashcards
Normal measurement of
-IVC
-Common iliac veins
-right common iliac vein
-left common iliac vein
-2.5 cm
-1.6-1.8 cm in diameter
-5.5 com LONG
-7.5 cm LONG
IVC SHOULD NOT EXCEED 3.7 cm
IVC is formed by
convergence of the common iliac veins,which empty lower extremities and pelvis
Congenital variations of IVC
double IVC-IVC located on left side
Absence of certain portions of IVC,or a combo of these.
-Variations are attributable to complex embryonic development of the ivc.
IVC tributaries that empty into the IVC as it courses superiorly and pierces diaphragm at the caval hiatus to enter right atrium of the heart.
renal veins, hepatic veins, lumbar veins and right gonadal vein
IVC is posterior to
The intestines and body of the liver
IVC located more posteriorly as it courses superiorly
Hepatic section of IVC is located
posterior to liver
Prerenal section of IVC is located
inferior to hepatic veins, slightly superior to renal veins
Postrenal section of IVC is difficult to see because of
overlying bowel gas
Right and left common iliac veins empty
lower extremities and pelvis at the level of the umbilicus
Ascending lumbar venous channels are important because
If IVC becomes blocked they connect common iliac veins,iliolumbar veins and lumbar veins with azygos and hemiazygos veins of the thorax.
Lumbar veins drain
posterior abdominal wall
-are 4 in number
-1st two join ascending lumbar veins and 3rd and 4th empty into ivc up to level of renal veins
Ascending lumbar veins join subcostal vein to form
Azygos vein on right side and hemiazygos on the left.
Iliolumbar veins anatomies with
common iliac veins.They course superiorly from region of iliac and poses muscle and 5th lumbar vertebra.
right gonadal vein is located
parallel to ivc and empties into anterior lateral aspect of IVC.ri
right renal vein sometimes assists right adrenal gland through the
right suprarenal vein
Left renal vein is ______ than right renal vein
longer
Left renal vein is located
posterior to a portion of splenic vein and pancreas tail and between aorta and SMA
-Has more tributaries than right renal.Ex.left gonadal vein and left suprarenal vein
When right suprarenal vein does not empty into right renal vein, it empties_____
directly into IVC, superior to right renal vein
Inferior phrenic veins
most superior branch of IVC,drains diapragm and empty into lateral aspect of ICV.
Diameter of IVC increases during____ and decreases during___
Valsava maneuver (inspiration)
Expiration
Asking patient to sniff will cause IVC to
momentarily collapse.
Why are venous walls thinner?
Because their tunica media is thin compared to that of arterial system
-Highly tensile vessel not needed because the venous network is a low-pressure system.
Primary function of IVC and its tributaries
return deoxygenated blood to heart.
What do the Valves in venous system do?
Prevent back flow of blood during diastole.
Momentum of blood during systole forces valves to ___.
Once momentum decreases and blood isn’t pushed forward, valves____, preventing retrograde flow
Open
Close
When valves don’t function this causes____
Retrograde blood flow
Blood is also moved forward by
decrease in thoracic pressure, which pulls blood into right atrium.IVC acts as transportation vehicle when this happens
Veins normally display
anechoic lumen with thin, bright echogenic walls.
Small moving echoes often noticed within lumen of IVC
reason for it is debatable.Could be viscosity of blood flow within the vessel.
In sagittal, epigastric area,hepactic section of IVC looks
Longitudinal,tubular,elastic located directly posterior to liver
In most superior section of liver, hepatic veins can be seen as
anchor and linear with nondescript walls
As hepatic veins approach IVC,they___
Increase in diameter.
Often notice bunny ear or reindeer sign pattern in transverse place
In transverse, left renal veins is seen
longitudinally as a curvilinear structure,anterior to aorta and posterior to SMA
IVC and branches are primarily evaluated to detect
intraluminal thrombosis and tumor invasion
IVC filters are used to
help prevent blood clots from traveling to and through the heart to the lungs,pulmonary embolus
The gold standard diagnostic application to evaluate venous system
Venography
is invasive and carries risks with contrast injections and x-rays
Causes of Thrombosis
hyper coagulability,malignancy,venous stasis and focal compression.
Tumor invasion commonly occurs in the
Renal veins and often extends to IVC.
Complex variation of ivc are
double IVC
LEFT POSITION IVC
ABSENCE OF A PORTION OF IVC (RARE)
Duplex doppler sonography
Asses flow dynamic of veins
-Proximal compression and distal augmentation also used to asses venous flow.
Normal venous flow pattern should be
Spontaneous and phasic
Phasic
changes with respiration
Color flow doppler
Determines flow characteristics in abdomen and extremities by quickly identifying flow and turbulence.
Continous-wave doppler
Helpful determining status of extremity veins.
-dopple signal amplified by a loudspeaker.
Impedance flow plethysmography
-measures the blood volume change of an area.
-strain gauge plethysmography–bilateral cuffs placed in proximal portion of extremities.
