stratum corneum

noun

stratum cor·​ne·​um -ˈkȯr-nē-əm How to pronounce stratum corneum (audio)
: the outermost layer of the epidermis that consists of keratin-rich corneocytes connected by desmosomes and embedded in a matrix of lipids (such as ceramides and cholesterol) arranged in bilayers and that regulates skin permeability, maintains hydration, provides structural integrity, and acts as a protective barrier (as against UV radiation, pathogens, and toxins)

Note: In humans, the stratum corneum is typically 12 to 20 cell layers thick but may be over 50 layers thick in the soles of the feet and less than 9 layers thick on the eyelids. The outer layers are continually shed with one corneocyte cell layer typically sloughed off every day as desmosomes are enzymatically broken down.

The stratum corneum barrier relies predominantly on the extracellular matrix, where lamellar bilayers block the outflow of water into the environment … .Peter M. Elias et al.
A primary function of the stratum corneum is to protect the underlying tissue from environmental injury.Discover

Examples of stratum corneum in a Sentence

Recent Examples on the Web Retinoids thin out the stratum corneum, which is the outermost layer of the skin that’s composed of dead skin cells. Jamie Friedlander Serrano, TIME, 17 Oct. 2024 These exfoliants remove dead skin cells from the outermost layer of the skin called the stratum corneum through the use of a grainy substance like a scrub or chemicals like glycolic acid. Jamie Wilson, Glamour, 8 Aug. 2024 Dehydration is when there is a lack of water in the stratum corneum or outer layer of the skin. Alicia Lansom, refinery29.com, 10 Jan. 2024 There are seven layers of skin, and most topical products, such as skincare products, only penetrate the stratum corneum (the outermost layer). Rachel Murphy, Verywell Health, 11 June 2024 See all Example Sentences for stratum corneum 

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'stratum corneum.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History

Etymology

New Latin, literally, horny layer

First Known Use

1857, in the meaning defined above

Time Traveler
The first known use of stratum corneum was in 1857

Dictionary Entries Near stratum corneum

Cite this Entry

“Stratum corneum.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/stratum%20corneum. Accessed 31 Oct. 2024.

Medical Definition

stratum corneum

noun
plural strata cornea
: the outer more or less horny part of the epidermis consisting chiefly of layers of dead flattened nonnucleated cells filled with keratin

More from Merriam-Webster on stratum corneum

Last Updated: - Updated example sentences
Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!