horn (redirected from horn button)

horn (horn)

1. cornu; a pointed projection such as the paired processes on the head of certain animals.

2. something shaped like the horn of an animal.horn´y

---

cicatricial horn  a hard, dry outgrowth from a cicatrix, commonly scaly and rarely osseous.

cutaneous horn  a horny excrescence on the skin, commonly on the face or scalp; it often overlies premalignant or malignant lesions.

horn of pulp  an extension of the pulp into an accentuation of the roof of the pulp chamber directly under a cusp or lobe of the tooth.

horn of spinal cord  the horn-shaped structure, anterior or posterior, seen in transverse section of the spinal cord; the anterior horn is formed by the anterior column of the cord and the posterior by the posterior column.

---

horn (hôrn)

n.

1. One of the hard, usually permanent structures projecting from the head of certain mammals, such as cattle, consisting of a bony core covered with a sheath of keratinous material.

2. A hard protuberance that is similar to or suggestive of a horn.

3. The hard, smooth keratinous material forming the outer covering of animal horns.

4. Any of the major subdivisions of the lateral ventricle in the cerebral hemisphere of the brain: the frontal horn, occipital horn, and temporal horn. Also called cornu.

---

horn,

a projection or protuberance on a body structure. Examples include the horn of the hyoid bone and the iliac horn.

---

horn

1. a pointed projection.

2. the processes carried on the foreheads of most ruminants and rhinoceroses including skin-covered bony knobs in giraffes, velvet-covered branched deciduous bony antlers of deer, branched deciduous keratinized processes in pronghorns and the familiar hollow horns of bovids. In these a horny sheath is composed of keratinized epithelial cells borne on a fibrous corium that is carried on a cornual process, an extension of the frontal bone. In mature cattle the cavity of the frontal sinus extends into the cornual process. Called also fighting horns.

Cattle and buffalo horns are classed as shorthorn (short, in-curving), lyre (see lyrate), crescent or sickle (large, inward curving, downward inclined), long (long, handlebar configuration).

---

horn aging

telling the age of a cattle beast by counting the rings at the base and adding one. Can give a guide but can also mislead. It is also capable of being faked and even obliterated by rasping or by dehorning.

horn amputation

see dehorning.

horn button

immature horn on the frontal bone of very young ruminants. Called also horn bud.

horn core cancer, horn cancer

is a squamous cell carcinoma of the mucosa of the frontal sinus which invades the horn core usually resulting in dehiscence of the horn. Has a very high prevalence in adult male cattle in India.

cicatricial horn

a hard, dry outgrowth from a cicatrix, commonly scaly and rarely osseous.

cutaneous horn

single or multiple firm projections ('horns') of keratin on the skin or footpads. They may originate from papillomas, keratoses or various skin tumors, particularly intracutaneous cornifying epithelioma, or in association with dermatophilosis or feline leukemia virus infection.

dorsal horn of spinal cord

the horn-shaped structure seen in transverse section of the spinal cord, formed by the dorsal column of the cord.

horn fly

see haematobiairritans.

horn nerve block

see cornual nerve block.

overgrown horn

malaligned shorthorn type horns which curve in too far and penetrate the skull, usually into a frontal sinus.

horn paste

made of hoof raspings mixed with lard. Packed into the clefts beside the bars of the sole in the horse's foot before the taking of a radiograph; avoids the misleading opacities created by the clefts on radiographs. Now usually replaced by Playdo.

horn pearls

microscopic structures found in some neoplasms of epithelial origin. Called also squamous or keratin pearls.

sebaceous horn

a hard outgrowth of the contents of a sebaceous cyst.

horn shears

devices used for removing horns. Most work as a guillotine and provide great leverage for cutting the horns at the base where a rim of skin can be included.

horn tubule

basic structural element in many horny outgrowths; produced by a dermal papilla, it bears some resemblance to a hair and grows approximately vertical to the dermal surface; it is united by intertubular horn to neighboring tubules.

ventral horn cell diseases

motor neuron diseases; rare in animals, but hereditary spinal muscular atrophy of Brittany spaniels is an example.

ventral horn of spinal cord

the horn-shaped structure seen in transverse section of the spinal cord, formed by the ventral column of the cord.

warty horn

a hard, pointed outgrowth of a wart.