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Discussion Starter · #1 ·
27-year-old woman received radiotherapy for the treatment of Hodgkin disease. There was no recurrence of her disease, but 8 years later she underwent surgery of the axillary and supraclavicular regions to alleviate pain arising from nerve and muscle adhesions that were a consequence of radiation damage. She is now admitted with severe dyspnea and cyanosis resulting from damage to the phrenic nerves. It is observed that while she is lying on her back, the abdominal wall paradoxically moves inward during inspiration. The explanation for this movement is which of the following?

A) Contraction of the diaphragm during inspiration causes the abdominal wall to move inward
B) Contraction of the intercostal muscles during inspiration causes the diaphragm to be drawn upward and the abdominal wall to be drawn inward
C) Contraction of the rectus abdominus muscles during inspiration causes inward motion of the abdomen
D) In the horizontal position, the reduction in thoracic volume required for inspiration is caused by upward movement of the abdominal viscera
E) Relaxation of the muscles of the thoracic wall during inspiration causes the abdominal wall to be drawn inward
 

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this sounds like subcostal retractions and the phrenic nerves supplying the diaphragm was affected leaving her with severe dyspnea and cyanosis. so definitely B. diaphragm not helping in inspiration anymore.
 

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B is the ans. cos diapghram is suppose to move downward on inspiration but when there is damage to the phrenic nerve it goes the opposite way. so B is most likely the correct ans.
 

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Discussion Starter · #5 ·
B is correct...

yup guys...B is correct...
During normal quiet breathing, inspiration is produced by simultaneous contraction of the diaphragm and the external intercostal muscles. The dome-shaped diaphragm flattens downward toward the abdomen, pressing the viscera and pushing the abdominal wall outward. At the same time, the intercostals raise the ribs, thereby increasing the volume of the thoracic cavity. In this patient, the diaphragm is paralyzed or weakened because the phrenic nerves innervating this sheet of muscle have been damaged. Contraction of the intercostals on inspiration then causes the pressure in the pleural space to become more negative and the diaphragm to be sucked upward toward the thorax. This paradoxical movement of the diaphragm induces the abdominal viscera to move upward toward the thorax, and the abdominal wall to move inward.
 
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