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* thoracic duct...
 #389826  
  successor - 03/04/09 07:03
 
  A patient develops a form of lung cancer that spreads to occlude
the thoracic duct. Edema involving which of the following sites might
be expected as a potential complication?
A. Entire left side and right leg
B. Entire right side and left leg
C. Left arm only
D. Right arm and right half of head only
E. Right arm only
 
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* Re:thoracic duct...
#1676873
  4weeksexam - 03/04/09 07:04
 
  it is A  
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* Re:thoracic duct...
#1676874
  successor - 03/04/09 07:08
 
  can u explain...  
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* Re:thoracic duct...
#1676884
  samomcos - 03/04/09 07:30
 
  Ans is 'A' and will also be accompanied by steatorrhea and pleural effusion.

plus some additional points:

1. A BRACHIOCEPHALIC VENOUS CATHETERIZATION IS INADVISABLE ON THE LESFT SIDE since the insertion of a needle into the angle formed by the confluence of the internal jugular and subclavian veins might well encounter the terminal portion of the thoracic duct. The brachiocephalic route for a central venous

2. THE ANATOMY OF THE THORACIC DUCT DETERMINES THE LOCATION OF PLEURAL EFFUSION SEEN WITH DUCT INJURY OR OBSTRUCTION. Because the thoracic duct crosses the mediastinum at the fifth thoracic vertebral body, lymphatic injury or obstruction below this level results in a right–sided pleural effusion. In contrast, disease above this level usually leads to a left–sided effusion.

3. DURING DIGESTION THE THORACIC DUCT IS DISTENDED WITH CHYLE.



This main lymphatic duct conveys all the lymph from the lower limbs, pelvis, abdomen, left side of the thorax and head and neck and left upper limb to the venous system; that is, all but the right superior quadrant of the body.
It drains the cisterna chyli, which is an elongated sac that lies on the right side of the bodies of the 1st and 2nd lumbar vertebrae below the diaphragm.
The thoracic duct passes superiorly from the cisterna chyli through the aortic hiatus in the diaphragm on the right side of the aorta. In the posterior mediastinum, the thoracic duct ascends among the thoracic aorta on its left, the azygos vein on its right, the esophagus anteriorly, and the vertebral bodies and the origins of the right posterior intercostal arteries posteriorly.
At about the level of the sternal angle the thoracic duct deviates to the left, posterior to the esophagus and ascends through the superior mediastinum into the root of the neck to empty into the venous system at the union of the left internal jugular and subclavian veins.
The duct has a number of valves, which prevent lymph flowing downwards and give it a beaded appearance.
The cysterna chyli receives lymph from the lower limbs, pelvis and abdomen. The thoracic duct receives the left bronchomediastinal trunk in the thorax, and in the neck the left jugular and left subclavian lymph trunks. All these trunks can open independently into the left internal jugular or subclavian vein.
Because the thoracic duct is thin walled and may be colorless, it may be difficult to identify during surgical procedures. If the thoracic duct is cut or torn during an accident, chyle (L. chylus, juice) escapes from it. This milky fluid contains a considerable amount of fine fat droplets. Leakage of chyle may be prevented by tying off the thoracic duct. The lymph then returns to the venous system by other lymph channels, which join the duct superior to the ligature.
 
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* Re:thoracic duct...
#1676891
  successor - 03/04/09 08:04
 
  why B is not the ans...?  
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* Re:thoracic duct...
#1676899
  samomcos - 03/04/09 08:35
 
  bcz it drains everything except right upper limb and right side of head.  
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* Re:thoracic duct...
#1676900
  vspkumar - 03/04/09 08:35
 
  Ans is A  
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* Re:thoracic duct...
#1676904
  successor - 03/04/09 08:42
 
  both A and B options seems correct.... bcoz, theres is nothing like only in option B aswell..
plz clarify me.
 
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* Re:thoracic duct...
#1676915
  vspkumar - 03/04/09 08:51
 
  B is incorrect because entire right side of the body is not drained by thoracic duct. Right Superior Quadrant is drained by Right lymphatic Duct.

Hence Answer is A
 
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* Re:thoracic duct...
#1676955
  bilal1 - 03/04/09 10:10
 
  ans is aa b/c it drains lymph from both side of body below diaphragm and lt side of body above diapram . it empties into lt subclavian vein.  
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* Re:thoracic duct...
#1677015
  drbkc - 03/04/09 10:55
 
  one more anatomical point abt

right lymphatic duct also drains LEFT LOWER LOBE OF THE LUNG
 
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