Diaphragm paralysis definitively diagnosed by ultrasonography and postural dependence of dynamic lung volumes after seven decades of dysfunction.

Unilateral diaphragm paralysis is an important and often unrecognized cause of dyspnea. In patients with appropriate risk factors, such as prior head and neck surgery and presentation of positional dyspnea or dyspnea on submersion, unilateral diaphragmatic paralysis should be considered. We present our approach to the diagnosis of diaphragm paralysis and demonstrate the utility of upright/supine spirometry and M-mode ultrasonography in these patients' evaluation.