spinous layer

It divides to form the outer spinous layer (stratum spinosum).

The histologic appearance is thought to be caused by water within the cells of the spinous layer causing the light to reflect back as whitish.

Stratum spinosum (spinous layer)

However during inflammation, it is expressed in the spinous layer of the skin, the second layer from the bottom of four layers as a response to the inflammation.

The stratum spinosum (or spinous layer) is a layer of the epidermis found between the stratum granulosum and stratum basale.

It is found largely in the upper spinous layer of epidermal keratinocytes and mutations in the gene encoding this protein have been associated with ichthyosis bullosa of Siemens.

Tissue biopsy is not indicated, but when taken, the histologic appearance is one of increased epithelial thickness, broadening and eleongation of the rete ridges, parakeratosis and intracellular edema of the spinous layer.

In the upper spinous layer and stratum granulosum layer of the epidermis, lamellar bodies are secreted from keratinocytes, resulting in the formation of an impermeable, lipid-containing membrane that serves as a water barrier and is required for correct skin barrier function.