What does the term "nail pterygium" describe?

Nail pterygium refers to a condition where there is an abnormal growth of skin that extends over the nail plate from the eponychium (the cuticle area) onto the nail itself. This can often be associated with various skin disorders or injuries. The term specifically describes the stretchy, often inflamed skin that may compromise the normal appearance and function of the nail.

In contrast, the other options describe different nail conditions that do not relate to the actual growth of skin over the nail. Thickening of the nails pertains to increased nail hardness or density, discoloration refers to changes in color often due to health issues or external factors, and very thin, soft nails indicate brittleness or weakness but do not involve the skin surrounding the nail. Understanding nail pterygium and its implications is important for recognizing nail health conditions.