Why don't epidermal ridges form in thin skin?

Thin Skin. The epidermis differs from that of thick skin in having thinner stratum spinosum, granulosum, and corneum, and lacks the stratum lucidum (Thin Skin 1). The dermis is not arranged in ridges, but does project into the epidermis as true papillae. However, no epidermal ridges are produced

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