This test is used for determining the presence of hyperinflated lungs (as in COPD) or phrenic nerve palsy. It uses percussion on the posterior thorax.
Performing the Test
Percuss along the posterior chest to get a rough idea of where the diaphragm lies under normal breathing. The lungs will be tympanic on percussion whereas the retroperitoneum below the diaphragm will be dull.
Ask the patient to fully inspire.
Percuss the new level of dullness and mark this as the inferior level of diaphragmatic excursion.
Ask patient to fully expire.
Percuss the new level of dullness and mark this as the superior level of diaphragmatic excusion.
Repeat on both sides, comparing for symmetry.
Diaphragmatic excursion is usually 5-6 cm.
Bickley LS. The thorax and lungs. In: Bickley LS, Szilagyi PG. Bates' Guide to Physical Examination and History Taking. 10th ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2009:283-321.