Another possible mechanism is thickening of the stratum spinosum (acanthosis).

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

They divide to form the keratinocytes of the stratum spinosum, which migrate superficially.

They are pushed upward into the stratum spinosum by the continuous formation of new cells in the basal layer.

They are present in all layers of the epidermis, but are most prominent in the stratum spinosum.

Keratinization begins in the stratum spinosum.

Keratinocytes migrating from the underlying stratum spinosum become known as granular cells in this layer.

Stratum spinosum (spinous layer)

It implies increased thickness of the Malpighian layer (stratum basale and stratum spinosum).

Vitamin D is produced in the two innermost strata, the stratum basale and stratum spinosum.

The term Malpighian layer (stratum malpighi) is usually defined as both the stratum basale and stratum spinosum.

They make up the stratum spinosum (prickly layer) of the epidermis and provide a continuous net-like layer of protection for underlying tissue.

The highest concentrations of 7-dehydrocholesterol are found in the epidermal layer of skin, specifically in the stratum basale and stratum spinosum.

Involucrin is synthesised in the stratum spinosum and cross linked in the stratum granulosum by the transglutaminase enzyme that makes it highly stable.

The resulting vesicles are an intraepidermal clefts between the stratum corneum and stratum spinosum and is located above the basal cells (suprabasal).

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

The epidermis has five layers of its own: stratum germinativum, stratum spinosum, stratum granulosum, stratum lucidum, and stratum corneum.

The dermal papillae may be exposed after top layers of the dermis (stratum corneum, stratum granulosum, stratum spinosum and stratum basale) have been removed.

The epidermis consists of five strata; from outer to inner they are: the stratum corneum, stratum lucidum, stratum granulosum, stratum spinosum, and stratum basale.

They are surrounded by an oily substance that is the result of the exocytosis of lamellar bodies accumulated while the keratinocytes are moving through the stratum spinosum and stratum granulosum.

Under normal circumstances, ample quantities of 7-dehydrocholesterol (about 25-50 mg/cm of skin) are available in the stratum spinosum and stratum basale of human skin to meet the body's vitamin D requirements.

Optical Coherence Tomography tomogram of fingertip, depicting stratum corneum ( 500 m thick) with stratum disjunctum on top and stratum lucidum (connection to stratum spinosum) in the middle.

The epidermis is the most superficial layer of skin, a squamous epithelium with several strata: the stratum corneum, stratum lucidum, stratum granulosum, stratum spinosum, and stratum basale.

They have thickening of the stratum corneum (hyperkeratosis), thickening of the stratum spinosum (acanthosis), thickening of the stratum granulosum, rete ridge elongation, and large blood vessels at the dermoepidermal junction.

Also, the term is occasionally used synonymously as the prickle cell layer (although prickle cell layer generally is defined as the stratum spinosum specifically) or to designate a part of the stratum corneum.