The separation of the prepuce is the human penis is essentially a process of keratization of the intervening epithelium. It begins anteriorly and posteriorly at about the same time and proceeds toward the center. When confined on all sides the separation manifests itself as an epithelial pearl formation. On the surface, as is possible in the anterior region, it appears as a desquamation. Pearl formation is first seen in the enlarged posterior extremity of the glandar lamella, the site of the sulcus in the adult, approximately the sixth month of foetal life.
Later pearl appear at intervals anteriorly along the course of the lamella.
At first they are mere arrangements of cells in whorl-like fashion, but later their centers keratinize and leave a cavity. To effect a continuous separation of the prepuce, these cavities may actually coalesce or they may be united by a longitudinal keratinization of the epithelium intervening between the pearls. Separation is not completed at birth, but is accomplished sometime during infancy or early childhood. Unless the prepuce has been retracted, slight adhesions may persist in the posterior regions of the glandar lamella at 5 and 6 months. Separation is sufficient at the 10-day stage to allow mechanical retraction without danger of a tear, apparently an important factor in completing the division.