Ridged toe nails, also known as folded up toe nails, are a form of toe nail abnormality that may affect individuals of all ages and sexes. This condition is usually described as the appearance of multiple crosswise ridges or folds on the surface of the toenail. https://articlebiz.com/article/1052041687-what-are-plicatured-toe-nails-and-what-can-be-done-about-them