337.The answer is b.(Moore and Dalley, pp 40, 1060. Hansen and Lambert,
p 321.)A Pancoast tumor in the apex of the right lung may compress the
right brachiocephalic vein with resultant venous engorgement of the right
arm and right side of the face and neck. In addition, there may be com-
pression of the brachial artery, the sympathetic chain, and recurrent laryn-
geal nerve with attendant deficits. The left cervical rib (answer a)is on the
wrong side. An aneurysm of the aortic arch (answer c)could reduce pulse
pressures as the great vessels are occluded, but it could notexplain the
venous congestion. A right pneumothorax (answer d)wouldnotaffect
blood flow within the right arm. Thoracic duct blockage in the posterior
mediastinum(answer e)would be unlikely to affect only the right arm.
338.The answer is c.(Moore and Dalley, p 126.)Large aspirated objects
tend to lodge at the carina (both lungs affected) (answer a).Smaller
objects usually lodge in the right inferior lobar bronchus [not superior
(answer e)] because the right mainstem (primary) bronchus is generally
more vertical in its course than the left (answers b and d)and of greater
diameter. In addition, the takeoff angle of the right lower lobe bronchus is
less acute than that of the right middle lobe, thereby continuing in the gen-
eral direction of both the right mainstem bronchus and trachea. Blockage
of the airway will produce absence of breath sounds within the lobe and
eventual atelectasis, collapse.
339.The answer is a.(Moore and Dalley, pp 118–119.)The sampling of
pleural fluid is called thoracocentesis. The nature of the fluid will deter-
mine the appropriate course of treatment. Since the sampling is being per-
formed at the midaxillary line you would pass through all three layers of
muscles. Further anteriorly, the external intercostal muscle turns membra-
nous, while near the transverse process of the ribs the innermost intercostal
muscle becomes membranous (See Moore and Dalley p 97). None of the
other answers (b, c, d, or e)are correct.
340.The answer is d.(Moore and Dalley, pp 150–151.)Pregnancy increases
the chances of venous emboli, which might lead to stroke because emboli
might bypass the lung by passing through the ASD. In addition, there are
clamshell devices that may be inserted intravenously to repair the ASD that
donotrequire open-heart surgery. Normally emboli that form in the blood
480 Anatomy, Histology, and Cell Biology