Why do people have wrinkles on their knuckles?

Wrinkles on knuckles are primarily caused by the natural aging process, where the skin loses collagen and elasticity over time. Additionally, the skin on the knuckles is relatively thin and often experiences frequent movement and stretching, which can contribute to the formation of wrinkles. Environmental factors, such as sun exposure and dehydration, can also exacerbate the appearance of wrinkles in this area.