That little fold or crease in the outer corner of your eye, or on your forehead, or perhaps, falling from your nose towards the corners of your mouth. Interestingly enough, if you biopsy a wrinkle, and look at it under the microscope, the wrinkle is not evident. As a matter of fact, there is no anatomical structure associated with either a skin wrinkle or crease. And if you compare skin from a wrinkle with adjacent non-wrinkled skin, there is no histological difference seen in either a light microscope or an electron microscope.
In healthy skin, there is a normal physiological balance between the production of new cells and the shedding of the old ones. The outmost layer of skin, the stratum corneum, is approximately 20 layers of non-living, yet functional, cells called corneocytes. They are held together by protein bridges called desmosomes. Desquamation is the process by which these protein bridges are enzymatically dissolved allowing the shedding of the most superficial cells. The enzymes responsible for dissolving these bridges can only function in a well hydrated environment.