Contour maps of auscultatory percussion in healthy subjects and patients with large intrapulmonary lesions.

Auscultatory percussion of the chest is a clinical examination method that has been purported to detect intrapulmonary masses by their effect on transmission of the percussion note to the posterior chest. Recent findings from this laboratory suggested that the sound of sternal percussion may actually travel through the chest cage and not the lung parenchyma. To investigate this possibility further, we recorded the sound produced by sternal percussion at 63 evenly spaced points over the posterior chest wall of 3 healthy subjects and 4 patients with large, discrete intrathoracic lesions in the right upper lobe (2 patients), left lower lobe, and left upper lobe (1 patient each). We constructed 3-dimensional contour maps of the indices of sound amplitude and frequency to view graphically the pattern of distribution of the sound. Examination of the maps revealed areas of increased amplitude in the zones of projection of some osseous structures, especially the scapulae, both in the healthy subjects and patients. No disturbances in the pattern reflecting the presence of mediastinal structures or intrathoracic lesions were found despite the existence of deeply situated lung masses as large as 10 cm in diameter. These findings support the argument that the sound of sternal percussion travels to the posterior chest predominantly through chest wall structures.