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
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