callus

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(kăl'əs) pronunciation
n., pl., -lus·es.
    1. A localized thickening and enlargement of the horny layer of the skin. Also called callosity.
    2. The hard bony tissue that develops around the ends of a fractured bone during healing.
  1. Botany.
    1. Undifferentiated tissue that develops on or around an injured or cut plant surface or in tissue culture.
    2. The hardened, sometimes sharp base of the floret of certain grasses.
intr.v., -lused, -lus·ing, -lus·es.
To form or develop such hardened tissue. See Usage Note at callous.

[Latin, masculine of callum.]



means 'a hard thick area of skin or tissue', and should be distinguished from callous, which is related to it but now much more often means 'unfeeling, insensitive'.

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In botany, soft tissue that forms over a wounded or cut plant surface, leading to healing. A callus arises from cells of the cambium. When a callus forms, some of its cells may organize into growing points, some of which in turn give rise to roots while others produce stems and leaves. Thus a callus may be capable of regenerating an entire plant.

For more information on callus, visit Britannica.com.

1. Tissue containing blood and bone cells that form around bone following a fracture. Callus formation is an essential part of healthy bone repair.

2. See callosity.

corns and calluses, thickenings of the outer layer of skin where there is irritation or constant pressure. Corns are cone-shaped with their points protruding into the dermis, or inner layer of skin. They usually have hard, shiny surfaces surrounded by red, painful areas. Soft-surfaced corns sometimes develop between overlapping toes where there is an accumulation of moisture. Treatment of corns is directed at the relief of irritation or pressure, e.g., wearing properly fitted shoes; they can also be softened by pastes and ointments or removed by a physician. Calluses typically involve only the outermost layers of skin and are not usually painful; they tend to disappear once the source of irritation has been removed. See bunion.



  1. The corklike tissue that is developed to cover wounds in the bark of a tree or shrub.
  2. A zone of rapidly dividing cells at the base of a cutting that precedes root formation.


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pronunciation

IN BRIEF: n. - (botany) an isolated thickening of tissue, especially a stiff protuberance on the lip of an orchid; Bony tissue formed during the healing of a fractured bone; An area of skin that is thick or hard from continual pressure or friction.

Tutor's tip: The doctor was "callous" (insensitive, cold in manner) when I showed her the painful "callus" (thick hard skin layer) on my finger.

LearnThatWord.com is a free vocabulary and spelling program where you only pay for results!

  1. a mass of relatively unspecialized tissue that develops at wound sites in plants, forming a protective covering. Callus cells are used in tissue culture as the starting material for the propagation of plant clones.
  2. tissue formed during the healing of broken bone.

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1. localized hyperplasia of the horny layer of the epidermis due to pressure or friction. In dogs, these often form over pressure points such as the elbow, hock and (in some breeds) sternum, particularly if the animal is sleeping on a hard surface.
2. an unorganized network of woven bone formed about the ends of a broken bone; it is absorbed as repair is completed (provisional callus), and ultimately replaced by true bone (definitive callus).

  • bridging c. — bridging the callus gap.
  • external c. — around the outside of a fracture.
  • hard c. — fully mineralized.
  • hypertrophic c. — a form of delayed healing in which fibrocartilage forms between fracture fragments, resulting in a false callus. Called also elephant's foot callus.
  • internal c. — between the ends of fractured bones.
  • periosteal c. — new bone formed by the proliferation of periosteal osteogenic cells.
  • provisional c. — a subsequently remodeled callus.
  • c. pyoderma — secondary bacterial infection, particularly of pressure point calluses in dogs; can be extensive with deep pyogenic inflammation.
  • soft c. — the originating fibobrocellular tissue before calcification.
  • sternal c. — may develop over a prominent sternum in some breeds of dogs, particularly Dachshunds, in response to pressure.
  • temporary c. — see provisional callus (above).
(kal′əs)
n

The tissue near and about the broken fragments of a bone that becomes involved in the repair of the fracture through various stages of exudate, fibrosis, and new bone formation.

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categories related to 'callus'

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Random House Word Menu by Stephen Glazier
For a list of words related to callus, see:
  • Signs and Symptoms - callus: hard thickening of area of skin undergoing rubbing, esp. on hands or feet; mass of tissue forming around fractured bone ends


Callus
Classification and external resources

Examples of callus found on the toe
ICD-10 L84
ICD-9 700
MeSH D002145

A callus (or callosity) is a toughened area of skin which has become relatively thick and hard in response to repeated friction, pressure, or other irritation. Rubbing that is too frequent or forceful will cause blisters rather than allow calluses to form. Since repeated contact is required, calluses are most often found on feet because of frequent walking. Calluses are generally not harmful, but may sometimes lead to other problems, such as skin ulceration or infection.

Contents

Causes

Normally, a callus will form on any part of the skin exposed to friction over a long period of time. For example, people often develop calluses on the middle finger of their dominant hand due to writing with a pen or pencil. Another cause is from playing string instruments like the violin or the guitar; calluses will develop on the four left hand fingers used in holding the strings down to the fingerboard, and sometimes right hand fingers used for pizzicato or strumming. Calluses are also very common on the fingers of bassists who use both the pizzicato and slapping techniques. There are many activities that can result in the formation of a callus, and having one is sometimes viewed as a badge of honor.[1] Activities that are notorious for causing calluses include (but are not limited to) playing musical instruments, martial arts, many sports (specifically rowing and racket sports), weight training, dancing (especially ballet), digging, praying, chopping wood, and wearing high heels. Tenpin bowlers will often develop calluses on their thumbs and occasionally their middle fingers from frequent bowling.[2] Although often found on the foot (where the most pressure and friction are applied), calluses can occur anywhere on the body as a reaction to moderate, constant "grinding" pressure. It is the natural reaction of the palmar or plantar skin. Too much friction occurring too fast for the skin to develop a protective callus will cause a blister or abrasion instead.

Biologically, calluses are formed by the accumulation of terminally differentiated keratinocytes in the outermost layer of skin. Though the cells of calluses are dead, they are quite resistant to mechanical and chemical insults due to extensive networks of cross-linked proteins and hydrophobic keratin intermediate filaments containing many disulfide bonds.[3]

Sometimes a callus occurs where there is no rubbing or pressure. These hyperkeratoses can have a variety of causes. Some toxins, such as arsenic, can cause thick palms and soles. Some diseases, such as syphilis, can cause thickening of the palms and soles as well as pinpoint hyperkeratoses. There is a benign condition called keratosis palmaris et plantaris, which produces corns in the creases of the fingers and non-weight bearing spaces of the feet. Some of this may be caused by actinic keratosis, which occurs due to overexposure to sun or with age and hormonal shifts.

Corns

A corn (or clavus, plural clavi) is a specially-shaped callus of dead skin that usually occurs on thin or glabrous (hairless and smooth) skin surfaces, especially on the dorsal surface of toes or fingers. They can sometimes occur on the thicker palmar or plantar skin surfaces. Corns form when the pressure point against the skin traces an elliptical or semi-elliptical path during the rubbing motion, the center of which is at the point of pressure, gradually widening. If there is constant stimulation of the tissue producing the corns, even after the corn is surgically removed, the skin may continue to grow as a corn.[citation needed]

Painful corns

The hard part at the center of the corn resembles a funnel with a broad raised top and a pointed bottom. Because of their shape, corns intensify the pressure at the tip and can cause deep tissue damage and ulceration.[4] The scientific name for a corn is heloma (plural helomata). A hard corn is called a heloma durum, while a soft corn is called a heloma molle.

The location of soft corns tends to differ from that of hard corns. Hard corns occur on dry, flat surfaces of skin. Soft corns (frequently found between adjacent toes) stay moist, keeping the surrounding skin soft. The corn's center is not soft however, but indurated.

The specific diagnostic workup and treatments for corns may differ substantially from other forms of calluses

Prevention

Corns and calluses are easier to prevent than to treat. When it is not desirable to form a callus, minimizing rubbing and pressure will prevent callus formation. Footwear should be properly fitted,[5] gloves may be worn, and protective pads, rings or skin dressings may be used. People with poor circulation or sensation should check their skin often for signs of rubbing and irritation so they can minimize any damage.

Treatment

Calluses and corns may go away by themselves eventually, once the irritation is consistently avoided. They may also be dissolved with keratolytic agents containing salicylic acid, sanded down with a pumice stone or filed down with a callus shaver, or pared down by a professional such as a podiatrist or a foot health practitioner.[6]

Before 1937 (when commerce in medicinal cannabis was effectively banned by a federal law in the United States), topical corn remedies usually contained tincture of cannabis, whose antibacterial properties were an effective agent. In addition, the inclusion of cannabis provided the herbal green appearance expected by consumers of the day.[7]

Diabetes

People with diabetes face special skin challenges. Because diabetes affects the capillaries, the small blood vessels which feed the skin, thickening of the skin with callus increases the difficulty of supplying nutrients to the skin.[citation needed] Callus formation is seen in high numbers of patients with diabetes and together with absent foot pulses and formation of hammer toe,[8][9] this may be an early signs of individuals at an increased risk for foot ulcers.[8]

The stiffness of a callus or corn, coupled with the shear and pressure that caused it, may tear the capillaries or adjoining tissue, causing bleeding within the callus or corn. Often, bleeding within a callus is an early sign of diabetes, even before elevated blood sugars may be noticed. Although the bleeding can be small, sometimes small pools of blood or hematoma are formed. The blood itself is an irritant, a foreign body within the callus that makes the area burn or itch. If the pool of blood is exposed to the outside, infection may follow. Infection may also lead to ulceration. Luckily, this process can be prevented at several places, Diabetic foot infections are the leading cause of diabetic limb amputation.

Other meanings

In botany, the term is also used to describe a condition of thickened surfaces of leaves or other plant parts. A callus also can refer to an undifferentiated plant cell mass grown on a culture medium, which can be put into a bioreactor to produce genetically identical cells.

See also

Notes

  • Taber's Cyclopedic Medical Dictionary, 15th Edition, CL Thomas, M.D., M.P.H., editor, F.A. Davis Company, Philadelphia, PA, 1985.
  • The Merck Manual of Medical Information, Home Edition, R Berkow, M.D., et al., editors, Merck Research Laboratories, Whitehouse Station, NJ, 1997.

References

  1. ^ "Google Search". http://www.google.com/search?q=proud+calluses. 
  2. ^ "Google Search". http://www.tititudorancea.com/z/callus.htm. 
  3. ^ Tantisiriwat N, Janchai S (Dec 1991). "Transglutaminases: multifunctional cross-linking enzymes that stabilize tissues.". The FASEB Journal 5 (15): 3071–7. PMID 1683845. http://www.fasebj.org/content/5/15/3071.long. 
  4. ^ eMedicine > Clavus By Nanette Silverberg. Updated: Apr 9, 2010
  5. ^ Erstad, Shannon (6 March 2008). "Foot problems: Finding the right shoes". WebMD Medical Reference from Healthwise. Healthwise. "How do I find the right shoes?". http://www.webmd.com/a-to-z-guides/finding-the-right-footwear-for-your-foot-problem. Retrieved 2010-06-10. "You should not have to "break in" shoes if they fit properly." 
  6. ^ Corns and calluses: Treatments and drugs. Mayo Clinic. Retrieved July 23, 2009.
  7. ^ http://antiquecannabisbook.com/chap6/CornMed.htm
  8. ^ a b Alavi A, Sanjari M, Haghdoost A, Sibbald RG (April 2009). "Common foot examination features of 247 Iranian patients with diabetes". Int Wound J 6 (2): 117–22. doi:10.1111/j.1742-481X.2009.00583.x. PMID 19432661.  -12% having callus formation
  9. ^ Tantisiriwat N, Janchai S (July 2008). "Common foot problems in diabetic foot clinic". J Med Assoc Thai 91 (7): 1097–101. PMID 18839852.  -56% having callus present

External links


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Dansk (Danish)
n. - callus, bruskagtigt bindevæv dannet efter knoglebrud
v. intr. - danne hård hud, danne bruskagtigt bindevæv

Nederlands (Dutch)
eelt, litteken(weefsel), callus

Français (French)
n. - cal, cals, durillon
v. intr. - former des durillons

Deutsch (German)
n. - (Physiol.) Schwiele, Kallus, (Med.) Knochennarbe, (Bot.) Wundgewebe
v. - einen Kallus bilden

Ελληνική (Greek)
n. - (φυσιολ.) τύλος, κάλος

Italiano (Italian)
callosità, callo, durone, tiloma

Português (Portuguese)
adj. - calosidade
n. - calo (m), calo (m) ósseo (Med.)

Русский (Russian)
костная мозоль

Español (Spanish)
n. - callo
v. intr. - hacerse un callo

Svenska (Swedish)
n. - kallus, sårvävnad
v. - göra valkig

中文(简体)(Chinese (Simplified))
皮肤的硬结, 愈合组织, 胼胝, 结硬皮, 生老茧, 结痂

中文(繁體)(Chinese (Traditional))
n. - 皮膚的硬結, 癒合組織, 胼胝
v. intr. - 結硬皮, 生老繭, 結痂

한국어 (Korean)
n. - 굳은 살, 유합 조직
v. intr. - ~를 형성하다

日本語 (Japanese)
n. - 胼胝, たこ, 癒傷組織, カルス, 皮膚硬結

العربيه (Arabic)
‏(الاسم) جز متصلب من الجلد (فعل) يسبب أو يتسبب في تصلب الجلد‏

עברית (Hebrew)
n. - ‮יבלת (בעור), צלקת‬
v. intr. - ‮נוצרה (יבלת)‬


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