Final answer:
The stratum lucidum is the specialized layer of the epidermis only located on the palms and soles, sandwiched between the stratum granulosum and stratum corneum, providing extra protection.
Step-by-step explanation:
The layer of the epidermis only found on the palms of the hands and soles of the feet is known as the stratum lucidum. This layer is positioned between the stratum granulosum and stratum corneum. The stratum lucidum is comprised of dead keratinocytes that are densely packed with a clear protein called eleiden, derived from keratohyalin. This protein confers a transparent, or lucid, appearance to the cells in the stratum lucidum and is essential for the barrier properties of the skin, especially in areas subjected to increased friction and pressure, such as palms and soles. It provides an extra layer of protection, but contrary to the question statement, it is not located on the very outer surface of the skin; that designation belongs to the stratum corneum.