The tympanic membrane (TM) is an important hearing component that when ruptured causes severe hearing difficulty. It has been mainly characterized mechanically by measuring its displacements, vibration modes, impedance, and thickness. The objective of this research is to determine the relationship of the TM’s thickness obtained with confocal laser scanning microscopy (with scans along the Z axis) with the magnitude of the TM’s surface displacements measured with sound stimuli of 1.8, 5.2, and 12 kHz using digital holographic interferometry. In order to correlate the data, three regions of four healthy cats’ TMs are studied, with a particular finding that the thickness is not the same in these regions and, among samples, a feature readily noticed in the magnitudes of the displacements. Through the relationship of the data from the TM’s surface displacements with its thickness, it is now possible to confidently detect pathological changes in its structure by simply quantifying the magnitude of the former, a characteristic corroborated by the Pearson correlation coefficient (r).