Diaphragm and Phrenic Nerve Ultrasound in COVID‐19 Patients and Beyond

The diaphragm, the principle muscle of inspiration, is an under‐recognized contributor to respiratory disease. Dysfunction of the diaphragm can occur secondary to lung disease, prolonged ventilation, phrenic nerve injury, neuromuscular disease, and central nervous system pathology. In light of the global pandemic of coronavirus disease 2019 (COVID‐19), there has been growing interest in the utility of ultrasound for evaluation of respiratory...