Calcium and sulfur location in human nail.

Analytical electron microscopy was performed in order to elucidate the importance of calcium and sulfur to the hardness of nails. The free surfaces adsorb a considerable quantity of calcium from the environment. It is suggested that such adsorption occurs due to ion exchange. This concept is supported by the fact that the distribution of sulfur does not vary over the nail cross-section. Analytical electron microscopy offers unique possibilities of elemental distribution analysis in tissue fragments or sections from keratinized tissues.