Editing Hoof (section)

== Description ==
[[File:Horse hoof wild bare sagittal.jpg|thumb|Sagittal section of a wild [[horse hoof]]. <br>Pink: soft tissues; <br>light gray: bone; <br>cyan: tendons; <br>red: [[Dermis|corium]];<br>yellow: digital cushion; <br>dark gray: frog; <br>orange: sole; <br>brown: walls]]
The hoof surrounds the distal end of the [[Phalanx bone|second phalanx]], the [[distal phalanx]], and the [[navicular bone]].<ref name=":5">{{Cite journal|title=Basic Farriery for the Performance Horse|doi=10.1016/j.cveq.2007.12.002|pmid=18314044|volume=24|issue=1|journal=Veterinary Clinics of North America: Equine Practice|pages=203–218|year=2008|last1=O'Grady|first1=Stephen E.}}</ref> The hoof consists of the [[Nail (anatomy)|hoof wall]], the bars of the hoof, the sole and [[frog (horse anatomy)|frog]] and soft tissue shock absorption structures.<ref name=":5"/> The weight of the animal is normally borne by both the sole and the edge of the hoof wall. Hooves perform many functions, including supporting the weight of the animal, dissipating the energy impact as the hooves strike the ground or surface, protecting the tissues and bone within the hoof capsule, and providing traction for the animal. Numerous factors can affect hoof structure and health, including genetics, hoof conformation, environmental influences, and athletic performance of the animal. The ideal hoof has a parallel hoof-pastern axis, a thick hoof wall, adequate sole depth, a solid heel base and growth rings of equal size under the coronary band.<ref name=":5" />

There are four layers within the exterior wall of the hoof. From the outside, a hoof is made up of the stratum externum, the stratum medium, the stratum internum and the dermis parietis. The stratum externum and the stratum medium are difficult to distinguish, the stratum externum is thin and the stratum medium is what makes up the bulk of the hoof wall.<ref name=":0">{{Cite journal|last1=Goulet|first1=Catherine|last2=Olive|first2=Julien|last3=Rossier|first3=Yves|last4=Beauchamp|first4=Guy|date=2015-11-01|title=RADIOGRAPHIC AND ANATOMIC CHARACTERISTICS OF DORSAL HOOF WALL LAYERS IN NONlAMINITIC HORSES|journal=Veterinary Radiology & Ultrasound|language=en|volume=56|issue=6|pages=589–594|doi=10.1111/vru.12280|pmid=26226838|issn=1740-8261}}</ref> Inside the hoof wall is a [[laminae (horse hoof)|laminar junction]], a soft tissue structure that allows the hoof to withstand the demands of force transmission it undergoes.<ref name=":1">{{Cite journal |title=Shape, Orientation and Spacing of the Primary Epidermal Laminae in the Hooves of Neonatal and Adult Horses ''(Equus caballus)'' |journal=Cells Tissues Organs|volume=166 |issue=3 |pages=304–318 |doi=10.1159/000016744 |pmid=10765026 |year=2000 |last1=Douglas |first1=Janet E. |last2=Thomason |first2=Jeffrey J. |s2cid=36816180}}</ref> This tissue structure binds the inner surface of the hoof wall, the dermis parietis and the outer surface of the third phalanx.<ref name=":1" />

Most [[even-toed ungulate]]s (such as [[sheep]], [[goat]]s, [[deer]], [[cattle]], [[bison]] and [[pig]]s) have two main hooves on each foot, together called a [[cloven hoof]].<ref group=Note>The term "cloven hoof" therefore being a technical misnomer as nothing is actually "cloven".</ref> Most of these cloven-hooved animals also have two smaller hooves called [[dewclaw]]s a little further up the leg &ndash; these are not normally used for walking, but in some species with larger dewclaws (such as deer and pigs) they may touch the ground when running or jumping, or if the ground is soft. In the mountain goat, the dewclaw serves to provide extra traction when descending rocky slopes as well as additional drag on loose or slippery surfaces made of ice, dirt, or snow.<ref>{{cite book|title=A Beast the Color of Winter: The Mountain Goat Observed|url=https://books.google.com/books?id=SMnXTHE5iWMC&pg=PA52|date=1 February 2002|publisher=U of Nebraska Press|isbn=978-0-8032-6421-2|page=52}}</ref> Other cloven-hooved animals (such as [[giraffe]]s and [[pronghorn]]s) have no dewclaws.

In some so-called "cloven-hooved" animals, such as [[camel]]s, the "hoof" is not properly a hoof &ndash; it is not a hard or rubbery sole with a hard wall formed by a thick nail &ndash; instead it is a soft toe with little more than a nail merely having an appearance of a hoof.

Some [[odd-toed ungulate]]s ([[Equidae|equid]]s) have one hoof on each foot; others have (or had) three distinct hooved or heavily nailed toes, or one hoof and two dewclaws. The [[tapir]] is a special case, having three toes on each hind foot and four toes on each front foot.