Induced paralysis of the diaphragm imitates spontaneous paralysis, which is a natural protective reaction to divers pleuropulmonary irritations. The capacity of the thoracic cavity of the side affected, or of both sides if the paralysis is bilateral, is reduced by the upward displacement of the diaphragm.
A further reduction frequently results from a correlated increased declivity of the ribs and narrowed intercostal spaces (figs. 1 and 2). Moreover, the excursions of the ribs are restricted. Induced and spontaneous paralysis may be incomplete or complete, unilateral or bilateral, transient, temporary or permanent.1
Occasionally a transient bilateral paralysis is induced to arrest singultus, or a transient unilateral paralysis is used to facilitate transabdominal repair of diaphragmatic hernia. Commonly, temporary and permanent paralysis and atonicity are induced for purposes to be discussed later because of the following responses:
Reduction in the capacity of the thoracic cavity imposes a corresponding diminution in the