callus

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Related to external callus: internal callus, hypertrophic callus, callusing

callus

 [kal´us]
1. localized hyperplasia of the horny layer of the epidermis due to pressure or friction.
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).
A fracture with callus formation (arrow) is demonstrated corresponding to the base of the second metatarsal. From Thrall and Ziessman, 2001.

cal·lus

(kal'ŭs), Avoid substituting the adjective callous for this noun. Avoid substituting the nonword calloused for the past participle callused.
1. Synonym(s): callosity
2. A composite mass of tissue that forms at a fracture site to establish continuity between the bone ends; it is composed initially of uncallused fibrous tissue and cartilage, and ultimately of bone. Synonym(s): fracture callus
[L. hard skin]

callus

(kăl′əs)
n. pl. cal·luses
a. A localized thickening and enlargement of the horny layer of the skin. Also called callosity.
b. The hard bony tissue that develops around the ends of a fractured bone during healing.
intr.v. cal·lused, cal·lusing, cal·luses
To form or develop such hardened tissue. See Usage Note at callous.

callus

Botany
Undifferentiated plant tissue produced at wound edge, callus tissue can be grown in vitro and induced to differentiate by varying the ratio of the hormones auxin and cytokinin in the medium.
 
Dermatology
Callosity, tyloma—A focus of hyperkeratotic skin secondary to repeated friction or pressure.
 
Orthopaedics
A mass of indurated bony trabeculae and cartilage formed by osteoblasts early in healing fractures.
 
Podiatry
A focus of indurated hyperkeratotic skin with a smooth centre, which is usually avascular, caused by rubbing or pressure; typically seen on the plantar aspect beneath the metatarsal head, as well as on the heel and Achilles tendon.  

Aetiology
Increased intermittent pressure on the skin; abnormal varus or valgus of foot leading to uneven weight distribution; local bone defect (plantar flexed ray, heel spur), long metatarsal, extrinsic pressure (improper footwear); surgical scars or lacerations.
 
Management
Trimming of the hyperkeratosis to the central core, soaking (e.g., epsom salts), and shaved regularly; to redistribute weight-bearing, a full-sole orthotic, footwear change and a metatarsal pad or hammer-toe crest pad if needed.

Prevention
Properly fitted shoes.

callus

Callosity, tyloma Dermatology Localized hyperkeratosis of skin 2º to repeated friction or pressure Orthopedics A mass of indurated bony trabeculae and cartilage formed by osteoblasts early in healing fractures

cal·lus

(kal'ŭs)
1. Synonym(s): callosity.
2. A composite mass of tissue that forms at a fracture site to establish continuity between the bone ends; it is composed initially of uncallused fibrous tissue and cartilage, and ultimately of bone.

callus

(kal'us) [L., hardened skin]
Enlarge picture
CALLUS: (on the weight-bearing portion of the foot)
1. A circumscribed thickening and hypertrophy of the horny layer of the skin. It may be oval or elongated, gray or brown, slightly elevated, with a smooth burnished surface. It appears on the flexor surfaces of hands and feet and is caused by friction, pressure, or other irritation. See: illustration Synonym: callosity

Treatment

Salicylic acid or careful shaving will remove the callosity temporarily. Removal is made permanent only by elimination of the cause.

2. The osseous material woven between the ends of a fractured bone that is ultimately replaced by true bone during healing. See: porosis

definitive callus

The exudate found between two ends of a fractured bone that develops into true bone.

provisional callus

A temporary deposit between the ends of a fractured bone that is reabsorbed when true bone develops.

callus

1. A collection of partly calcified tissue, formed in the blood clot around the site of a healing fracture. Callus is readily visible on X-ray and indicates that healing is under way.
2. A skin thickening (see CALLOSITY).

callus

a mass of immature plant cells which can differentiate into mature tissues, depending upon the relative concentrations of plant growth hormones present. Callus can develop from EXPLANTS in laboratory tissue culture experiments but also occurs naturally at the end of cut or wounded surfaces of shoots and roots.

Callus

Thickened skin due to chronic rubbing or irritation.

cal·lus

(kal'ŭs)
1. Synonym(s): callosity.
2. A composite mass of tissue that forms at a fracture site to establish continuity between the bone ends.