Identifying anisotropic structural features beneath the human nail with differential polarization parameters

Abstract

In this work, we report a method of identifying anisotropic structural features beneath the nail with differential polarization parameters. First the form of the differential Mueller matrix of medium in terms of the average and the fluctuation parameters of the differential polarization parameters in backscattering configuration is derived. The results are then employed to identify anisotropic structures beneath the human nail. For the first time, to our knowledge, it was found that collagen fibrils of the layers of epidermal cells of nail bed, the layers of actively dividing cells of the stratum germinativum of nail matrix, and the longitudinal striations in nail root can be related to the covariance of the linear birefringence along the x-y laboratory axes and the 45°axes. Although some tissue constituents can be observed in images of both macroscopic and differential parameters, the tissue components revealed by differential polarization parameters cannot be discerned in any image of the macroscopic parameters.

Keywords

• Nail fold
• Optical coherence tomography
• Nail disease
• Polarization parameters
• Depolarization
• Birefringence