Final answer:
The last layer damaged if a splinter penetrates to the second epidermal layer from the surface of the palm is the stratum lucidum, which is found only in the thick skin of the palms and soles.
Step-by-step explanation:
The skin is composed of multiple layers, and the epidermis itself has several strata. When we consider the question of which epidermal layer would be the last damaged if a splinter penetrated to the second layer from the surface of the palm, we need to take into account the specific layers of the epidermis. In areas of thick skin such as the palms, the epidermis includes the stratum corneum, stratum lucidum, stratum granulosum, stratum spinosum, and stratum basale. The stratum lucidum exists only in the thick skin of the palms and soles and is located just above the stratum granulosum. Since the stratum corneum is the outermost layer and the stratum lucidum is directly beneath it, the last layer that would be damaged if a splinter reaches the second epidermal layer is the stratum lucidum.