Which of the following is true about nail grooves?

Nail grooves are indentations that run vertically or horizontally along the nail plate and can significantly impact the growth and appearance of nails. These grooves can indicate various health conditions or changes in the body, which may affect how the nail grows. For instance, if a groove develops due to trauma or illness, it can lead to changes in nail texture and growth patterns. Therefore, understanding that nail grooves can influence nail growth helps highlight their importance in both aesthetic and health contexts.

While some grooves may appear to be purely cosmetic, they often have underlying causes that can affect the nail's overall health and growth. The other choices misrepresent the nature of nail grooves: they are not limited to the toes, they can change over time based on health conditions, and they are not only cosmetic issues but can indicate more significant underlying health concerns.