The stratum lucidum is the layer of the epidermis that is not found in all types of skin.
The skin is the largest organ in the human body and is composed of three main layers: the epidermis, the dermis, and the hypodermis. The epidermis is the outermost layer and is responsible for protecting the body from the environment. It is composed of several layers of cells called keratinocytes, which produce a protein called keratin.
The epidermis has five layers, from deepest to most superficial:
- Stratum basale (or stratum germinativum): This is the deepest layer of the epidermis, containing continuously dividing cells.
- Stratum spinosum: This layer provides strength and flexibility to the skin.
- Stratum granulosum: In this layer, cells start to flatten and produce keratin.
- Stratum lucidum: This is a thin, clear layer found only in thick skin, such as the palms of the hands and soles of the feet.
- Stratum corneum: This is the outermost layer of the epidermis, composed of dead cells filled with keratin.
While the stratum basale, stratum spinosum, stratum granulosum, and stratum corneum are present in all skin, the stratum lucidum is only present in thick skin. Therefore, it is the layer that is not found in all skin. The presence of the stratum lucidum contributes to the unique characteristics of thick skin, such as fingerprints.
