Glossary of Nail Conditions


To the right is a diagram of the basic structure of the nail.  Some of the more important anatomical terms are:

Bed -- the portion of skin upon which the nail rests.

Eponychium -- the skin at the base of the nail.  It's also called the "proximal nail fold", as it is labeled in the diagram. 

-- the skin beneath the tip of the nail.

Lunula -- the white half-moon-shaped structure near the base of the nail.

Matrix -- another word for the nail root.

Additionally, there are many different tongue-twisting terms to describe nail conditions, so we thought we'd provide a glossary of terms you may hear relating to the nails.  

For more information on specific nail conditions, please visit our web page on information about nail disorders and their treatment.  

The glossary is in alphabetical order, but I'll start by mentioning that Onyx is the Greek word for nail, and Unguis is the Latin word for nail.  Knowing this makes it easier to see the derivation of many of the words below, many of which contain the prefix "onych-" or "ungui-".  

Anonychia -- the absence of a nail.  This word comes from the Greek prefix "a-", meaning "without", and "onych-" meaning "nail".  

Avulsion -- the removal of the nail.  May be done in a manner to allow the nail to grow back, or in a manner to prevent the regrowth of the nail.

Granuloma -- overgrowth of highly vascular (good blood supply) soft tissue, typically caused from chronic irritation of a nail, such as an ingrown nail.   (You can see an example of a granuloma in the reddish tissue on the sides of the nail pictured under the heading of ingrown nails.)  

Hangnail -- a small loose flap of skin next to a nail plate.  

Hapalonychia -- soft nails.  Same as onychomalacia.  

Incurvated Nails -- nails which are curved and dig into the side of the skin, but without breaking the skin and being truly ingrown.  

Ingrown Nails -- nails which are digging into the skin, thereby causing a break in the skin.  Ingrown nails are characterized by inflammation and because of the break in the skin, they are frequently infected.  We have a separate web page that discusses ingrown nails, and another web page that discusses nail surgery.  (See "onychocryptosis", "onychoincurvatum", "paronychia" and "granulation tissue" for related terms.)

Koilonychia -- spoon-shaped nails.

Leukonychia -- white discoloration of the nail, frequently an early sign of fungal infection.  When the discoloration is present as a line or series of lines as it is in the picture to the right, it is known as "leukonychia striata".  When the white discoloration is present as small white spots or dots, it is known as "leukonychia punctata".  Usually caused from trauma to the nail.

Onych-, onycha- or Onycho- is a prefix meaning "nail".  It comes from the Greek word for nail, "Onyx". 

Onychalgia -- pain of the nail.

Onychauxis -- thickening of the nail, often as a result of fungus (a condition known as "onychomycosis" or "tinea unguium").

Onychectomy -- Surgical removal of a nail.

Onychocryptosis -- another word for an ingrown nail.  We have a separate web page that discusses ingrown nails, and another web page that discusses nail surgery.

Onychodystrophy -- generalized term for any malformation of the nail.

Onychogryphosis -- severe overgrowth of nails to the extent that the nails have the appearance of a ram's horn.  (See picture to the right.)


Onychoheterotopia -- a nail in an abnormal location.  

Onychoincurvatum -- an incurvated nail, without necessarily being ingrown.  

Onychitis -- inflammation of the nail bed.

Onycholysis -- loosening and lifting of the nail plate from a border.

Onychomalacia -- soft nails.  Same as hapalonychia.  

Onychomycosis -- fungal nails.

Onychopathy -- the condition of diseased nails.  Synonymous with onychosis.

Onychophagia -- chewing of the nails.

Onychophosis -- callus in the nail groove, common with incurvated nails.  

Onychoptosis -- falling off of the nails.  Often preceded by onycholysis.

Onychorrhexis -- abnormal brittleness of the nails.

Onychosis -- the condition of diseased nails.  Synonymous with onychopathy.

Onychotillomania -- compulsive picking at a nail.

Onyx --  the Greek word for nail, and the origin of the prefixes "onych-", "onycha-", and "onych-"

Paronychia -- a bacterial infection of the skin surrounding the nail, usually as a result of an ingrown nail.   (See picture to the right.)

Platonychia -- increased curvature of the nail in the long axis, (where the nail is growing around the tip of the toe.  

Pterygium -- overgrowth of the cuticle.  (See picture to the right.)

Trachyonychia --  rough nail surfaces.

Tinea unguium -- fungus in the nail caused by dermatophytes.  (See "onychomycosis").

Unguis --  the Latin word for nail.  See "onyx".

Unguis incarnatus -- ingrowing Nail.




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The Achilles Foot Health Centre
S. A. Schumacher, D.P.M., F.A.C.F.A.S., F.A.C.F.A.O.M.  
Dr. S. A. Schumacher, Podiatric Corporation  

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