[Common disorders and diseases of the nails. Anatomy, physiology, disorders, clarification and therapy].

Disorders of anatomical variants of the nails are often seen in clinical practice. Their correction identification and interpretation are essential dermatological skills. The increasing emphasis on aesthetic considerations in dermatology means that even the slightest nail changes may assume significance for their patients. In order to skillfully evaluate nails, one must be familiar with the terminology and classification of nail disorders. The nail plate, nail bed and periungual tissue may also be affected. Longitudinal melanonychia is especially important as a possible clue to subungual melanoma.