American Academy of Professional Coders (AAPC) Practice Exam

What characteristic defines the stratum lucidum?

1. It is the thickest layer of skin

2. It is composed of living cells

3. It is a clear layer

4. It provides sensation

The correct answer is: It is a clear layer

The defining characteristic of the stratum lucidum is that it is a clear layer. This layer is located between the stratum corneum and the stratum granulosum in thick skin, such as that found on the palms of the hands and the soles of the feet. The presence of keratin and the arrangement of the cells contribute to its translucent appearance, which differentiates it from the layers above and below. While it is true that the skin has various layers, the stratum lucidum is particularly noted for its clarity, setting it apart visually from other skin layers. It is also important to note that the cells in the stratum lucidum are not actively living in the way cells in deeper layers are; instead, they have undergone a process of keratinization and are essentially more flattened and clearer compared to living cells found in layers like the stratum granulosum or stratum basale. In the context of the other characteristics mentioned in the choices, the stratum lucidum is not the thickest layer of skin, as that title typically belongs to the stratum corneum. Also, while it contributes to the overall structure of the epidermis, it is not primarily composed of living cells since its cells are mostly dead