Diseases of the Foot
Involution denotes a curving towards the nail bed of either or both of the lateral or medial edges of the nail plate. It might be so marked that the two sides of the nail practically meet and the nail bed becomes pinched between them. This can also be precipitated by the lateral squeeze produced by footwear. Involution results in a reduction of the circulation to the nail bed, it may ulcerate causing considerable pain.
In minor degrees, involution produces little or no discomfort, the main consideration is to ensure that the nail is trimmed or filed to the length and shape of the toe. The uncurved edges should be reduced with an emery board. Seek medical advice.