The hoof ( pl. : hooves ) is the tip of a toe of an ungulate mammal , which is covered and strengthened with a thick and horny keratin covering. Artiodactyls are even-toed ungulates, species whose feet have an even number of digits; the ruminants with two digits are the most numerous, e.g. giraffe , deer , bison , cattle , goat , pigs , and sheep . The feet of perissodactyl mammals have an odd number of toes, e.g. the horse , the rhinoceros , and the tapir . Although hooves are limb structures primarily found in placental mammals, hadrosaurs such as Edmontosaurus possessed hoofed forelimbs. The marsupial Chaeropus also had hooves.
41-412: The hoof surrounds the distal end of the second phalanx , the distal phalanx , and the navicular bone . The hoof consists of the hoof wall , the bars of the hoof, the sole and frog and soft tissue shock absorption structures. 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
82-647: A cloven hoof . Most of these cloven-hooved animals also have two smaller hooves called dewclaws a little further up the leg – 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. Other cloven-hooved animals (such as giraffes and pronghorns ) have no dewclaws. In some so-called "cloven-hooved" animals, such as camels ,
123-401: A side grinder or disc grinder , is a handheld power tool used for grinding (abrasive cutting) and polishing . Although developed originally as tools for rigid abrasive discs, the availability of an interchangeable power source has encouraged their use with a wide variety of cutters and attachments. Angle grinders can be powered by an electric motor or compressed air . The motor drives
164-505: A 2-3-3-3-3 formula for the hand , meaning that the thumb has two phalanges, whilst the other fingers each have three. In the distal phalanges of the hand the centres for the bodies appear at the distal extremities of the phalanges, instead of at the middle of the bodies, as in the other phalanges. Moreover, of all the bones of the hand, the distal phalanges are the first to ossify. The distal phalanges of ungulates carry and shape nails and claws and these in primates are referred to as
205-475: A geared head at a right-angle on which is mounted an abrasive disc or a thinner cut-off disc, either of which can be replaced when worn. Angle grinders typically have an adjustable guard and a side-handle for two-handed operation. Certain angle grinders, depending on their speed range, can be used as sanders , employing a sanding disc with a backing pad or disc. The backing system is typically made of hard plastic, phenolic resin, or medium-hard rubber depending on
246-442: A large variety of angle grinders to choose from when trying to find the right one for the job. The most important factors in choosing the right grinder are the power source ( battery , corded or pneumatic ) and the disc size. Other factors include power of the motor, rpm , and arbor size. Generally disc size and power increase together. Disc size is usually measured in inches or millimetres. Common disc sizes for angle grinders in
287-584: A piece. There are many different kinds of discs that are used for various materials and tasks, such as cut-off discs ( diamond blade ), abrasive grinding discs, grinding stones, sanding discs, wire brush wheels and polishing pads. The angle grinder has large bearings to counter side forces generated during cutting, unlike a power drill , where the force is axial. Angle grinders are widely used in metalworking and construction , emergency rescues and even for bicycle thefts. Generally, they are found in workshops, service garages and auto body repair shops. There are
328-405: A solid heel base and growth rings of equal size under the coronary band. 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
369-625: Is a great hazard to the face and eyes especially, as well as other parts of the body, and as such, a full face shield and other protective clothing must be worn. Angle grinders should never be used without their guard or handle attached. All workpieces should be securely clamped or held firmly in a vise. Through a sound pressure level and vibrations study conducted by the National Institute for Occupational Safety and Health , grinders under an unloaded condition ranged from 91 to 103 dBA . Angle grinders may be used for removing excess material from
410-529: Is an increase in the number of phalanges beyond the plesiomorphic mammal condition of three phalanges-per-digit. Hyperphalangy was present among extinct marine reptiles -- ichthyosaurs , plesiosaurs , and mosasaurs -- but not other marine mammals, leaving whales as the only marine mammals to develop this characteristic. The evolutionary process continued over time, and a very derived form of hyperphalangy, with six or more phalanges per digit, evolved convergently in rorqual whales and oceanic dolphins , and
451-519: Is colloquially called just a "flex", in Italy and in Spanish-speaking countries it is sometimes called "flexible". In Switzerland it is known as "Perles" from a popular brand of cutting tools. In Polish it is also known as "kątówka" or "gumówka" (= the rubber thing), which refers to the elasticity of certain types of disks. However they are never made out of true rubber due to fire hazard. In Russian, it
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#1732852067861492-681: Is harder for an electric grinder to maintain adequate power with smaller size. Electric grinders are more commonly used for larger, heavy duty jobs. However, there are also small electric grinders and large pneumatic grinders. Angle grinders have been used to remove wheel clamps from vehicles. The high-speed angle grinder was invented in 1954 by German company Ackermann + Schmitt ( FLEX-Elektrowerkzeuge GmbH ) in Steinheim an der Murr . Owing to this, in German, Dutch, Slovak, Czech, Polish, Croatian, Romanian, Hungarian, Bulgarian and Latvian, an angle grinder
533-443: The ungual phalanges . The term phalanx or phalanges refers to an ancient Greek army formation in which soldiers stand side by side, several rows deep, like an arrangement of fingers or toes. Most land mammals including humans have a 2-3-3-3-3 formula in both the hands (or paws ) and feet . Primitive reptiles usually had the formula 2-3-4-4-5, and this pattern, with some modification, remained in many later reptiles and in
574-400: The hands and feet of most vertebrates . In primates , the thumbs and big toes have two phalanges while the other digits have three phalanges. The phalanges are classed as long bones . Toe bones or phalanges of the foot. Note the big toe has no middle phalanx. People vary; sometimes the smallest toe also has none (not shown). The phalanges are the bones that make up the fingers of
615-460: The mammal-like reptiles . The phalangeal formula in the flippers of cetaceans (marine mammals) varies widely due to hyperphalangy (the increase in number of phalanx bones in the digits). In humpback whales , for example, the phalangeal formula is 0/2/7/7/3; in pilot whales the formula is 1/10/7/2/1. In vertebrates, proximal phalanges have a similar placement in the corresponding limbs, be they paw , wing or fin . In many species, they are
656-491: The metacarpals of the hand or metatarsals of the foot at the metacarpophalangeal joint or metatarsophalangeal joint . The intermediate phalanx is not only intermediate in location, but usually also in size. The thumb and large toe do not possess a middle phalanx. The distal phalanges are the bones at the tips of the fingers or toes. The proximal, intermediate, and distal phalanges articulate with one another through interphalangeal joints of hand and interphalangeal joints of
697-401: The "hands" — the metacarpal and phalangeal bones — are elongated to the extent that they serve little use beyond locomotion. The giraffe , the largest even-toed ungulate, has large terminal phalanges and fused metacarpal bones able to absorb the stress from running. The sloth spends its life hanging upside-down from branches, and has highly specialized third and fourth digits for
738-560: The "hoof" is not properly a hoof – it is not a hard or rubbery sole with a hard wall formed by a thick nail – instead it is a soft toe with little more than a nail merely having an appearance of a hoof. Some odd-toed ungulates ( equids ) 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. Hooves grow continuously. In nature, wild animals are capable of wearing down
779-561: The United States include 4, 4.5, 5, 6, 7, 9 and 12 inches, with the most popular sizes being the 4.5 and 5" size. In Europe the most common sizes for angle grinder discs are 115 and 125 millimeters. Discs for pneumatic grinders also come much smaller. Pneumatic grinders are generally used for lighter duty jobs where more precision is required. This is likely because pneumatic grinders can be small and light yet remain powerful, because they do not contain heavy copper motor windings, while it
820-413: The advent of stone tool-making. However, the intrinsic hand proportions of australopiths and the resemblance between human hands and the short hands of Miocene apes, suggest that human hand proportions are largely plesiomorphic (as found in ancestral species) — in contrast to the derived elongated hand pattern and poorly developed thumb musculature of other extant hominoids . In Neanderthals ,
861-564: The amount of flexibility desired. Angle grinders are used in metal fabrication shops and on construction sites. They are also common in machine shops , along with die grinders and bench grinders . The use of an angle grinder in cutting is not preferred as large amounts of harmful sparks and fumes (and particulates ) are generated when compared with using reciprocating saw or band saw . Angle grinders produce sparks when cutting ferrous metals. They also produce shards cutting other materials. The blades themselves may also break. This
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#1732852067861902-533: The apical tufts were expanded and more robust than in modern and early upper Paleolithic humans. A proposal that Neanderthal distal phalanges was an adaptation to colder climate (than in Africa) is not supported by a recent comparison showing that in hominins , cold-adapted populations possessed smaller apical tufts than do warm-adapted populations. In non-human, living primates the apical tufts vary in size, but they are never larger than in humans. Enlarged apical tufts, to
943-451: The bulk of the hoof wall. Inside the hoof wall is a laminar junction , a soft tissue structure that allows the hoof to withstand the demands of force transmission it undergoes. This tissue structure binds the inner surface of the hoof wall, the dermis parietis and the outer surface of the third phalanx. Most even-toed ungulates (such as sheep , goats , deer , cattle , bison and pigs ) have two main hooves on each foot, together called
984-427: The distal phalanges of the finger, are smaller and are flattened from above downward; each presents a broad base for articulation with the corresponding bone of the second row, and an expanded distal extremity for the support of the nail and end of the toe. In the hand, the distal phalanges are flat on their palmar surface, small, and with a roughened, elevated surface of horseshoe form on the palmar surface, supporting
1025-406: 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,
1066-404: The equine world, the expression, "no foot, no horse" emphasizes the importance of hoof health. Hoof care is important in the equine industry . Problems that can arise with poor horse hoof care include hoof cracks, thrush, abscesses and laminitis . A cow hoof is cloven, or divided, into two approximately equal parts, usually called claws. Approximately 95% of lameness in dairy cattle occurs in
1107-417: The extent they actually reflect expanded digital pulps, may have played a significant role in enhancing friction between the hand and held objects during Neolithic toolmaking. Among non-human primates phylogenesis and style of locomotion appear to play a role in apical tuft size. Suspensory primates and New World monkeys have the smallest apical tufts, while terrestrial quadrupeds and Strepsirrhines have
1148-519: The feet. Lameness in dairy cows can reduce milk production and fertility, and cause reproductive problems and suffering. For dairy farm profitability, lameness, behind only infertility and mastitis , is the third most important cow health issue. Hoof trimmers trim and care for bovine hooves, usually dairy cows . Hooves can be trimmed with a sharp knife while the cow is restrained and positioned with ropes. Professional hoof-trimming tend to use angle grinders and some type of hoof trimming crush to make
1189-408: The finger pulp. The flat, wide expansions found at the tips of the distal phalanges are called apical tufts. They support the fingertip pads and nails. The phalanx of the thumb has a pronounced insertion for the flexor pollicis longus (asymmetric towards the radial side), an ungual fossa, and a pair of unequal ungual spines (the ulnar being more prominent). This asymmetry is necessary to ensure that
1230-444: The foot . Each phalanx consists of a central part, called the body , and two extremities. In the foot, the proximal phalanges have a body that is compressed from side to side, convex above, and concave below. The base is concave, and the head presents a trochlear surface for articulation with the second phalanx. The middle are remarkably small and short, but rather broader than the proximal. The distal phalanges, as compared with
1271-448: The foot differ from the hand in that they are often shorter and more compressed, especially in the proximal phalanges, those closest to the torso. A phalanx is named according to whether it is proximal , middle, or distal and its associated finger or toe. The proximal phalanges are those that are closest to the hand or foot. In the hand, the prominent, knobby ends of the phalanges are known as knuckles . The proximal phalanges join with
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1312-428: The hand and the toes of the foot. There are 56 phalanges in the human body, with fourteen on each hand and foot. Three phalanges are present on each finger and toe, with the exception of the thumb and big toe , which possess only two. The middle and far phalanges of the fourth and fifth toes are often fused together (symphalangism). The phalanges of the hand are commonly known as the finger bones. The phalanges of
1353-497: The hoof as it continuously grows, but captive domesticated species often must undergo specific hoof care for a healthy, functional hoof. Proper care improves biomechanical efficiency and prevents lameness. If not worn down enough by use, such as in the dairy industry, hooves may need to be trimmed. However, too much wear can result in damage of the hooves, and for this reason, horseshoes and oxshoes are used by animals that routinely walk on hard surfaces and carry heavy weight. Within
1394-455: The insertion of the flexor pollicis longus . Another ridge at the base serves for the insertion of the extensor aponeurosis . The flexor insertion is sided by two fossae — the ungual fossa distally and the proximopalmar fossa proximally. The number of phalanges in animals is often expressed as a "phalangeal formula" that indicates the numbers of phalanges in digits, beginning from the innermost medial or proximal. For example, humans have
1435-514: The largest. A study of the fingertip morphology of four small-bodied New World monkey species, indicated a correlation between increasing small-branch foraging and reduced flexor and extensor tubercles in distal phalanges and broadened distal parts of distal phalanges, coupled with expanded apical pads and developed epidermal ridges. This suggests that widened distal phalanges were developed in arboreal primates, rather than in quadrupedal terrestrial primates. Whales exhibit hyperphalangy. Hyperphalangy
1476-470: The longest and thickest phalanx ("finger" bone). The middle phalanx also has a corresponding place in their limbs, whether they be paw , wing , hoof or fin . The distal phalanges are cone-shaped in most mammals, including most primates, but relatively wide and flat in humans. The morphology of the distal phalanges of human thumbs closely reflects an adaptation for a refined precision grip with pad-to-pad contact. This has traditionally been associated with
1517-605: The process quicker and less physically demanding on the hoof trimmer. A hoof trimmer using modern machinery may trim the hooves of more than 10,000 cows per year. The trimmer shapes the hooves to provide the optimal weight-bearing surface. A freshly trimmed hoof may be treated with copper sulfate pentahydrate to prevent foot rot . Hooves have historical significance in ceremonies and games. They have been used in burial ceremonies. Phalanx bone The phalanges / f ə ˈ l æ n dʒ iː z / ( sg. : phalanx / ˈ f æ l æ ŋ k s / ) are digital bones in
1558-435: The purpose. They have short and squat proximal phalanges with much longer terminal phalanges. They have vestigial second and fifth metacarpals, and their palm extends to the distal interphalangeal joints . The arboreal specialization of these terminal phalanges makes it impossible for the sloth to walk on the ground where the animal has to drag its body with its claws. Angle grinder An angle grinder , also known as
1599-439: The support of the nail and end of the toe. The phalanx ends in a crescent-shaped rough cap of bone epiphysis — the apical tuft (or ungual tuberosity/process) which covers a larger portion of the phalanx on the volar side than on the dorsal side. Two lateral ungual spines project proximally from the apical tuft. Near the base of the shaft are two lateral tubercles. Between these a V-shaped ridge extending proximally serves for
1640-414: The thumb pulp is always facing the pulps of the other digits, an osteological configuration which provides the maximum contact surface with held objects. In the foot, the distal phalanges are flat on their dorsal surface. It is largest proximally and tapers to the distal end. The proximal part of the phalanx presents a broad base for articulation with the middle phalanx, and an expanded distal extremity for
1681-441: Was likely associated with another wave of signaling within the interdigital tissues. In ungulates (hoofed mammals) the forelimb is optimized for speed and endurance by a combination of length of stride and rapid step; the proximal forelimb segments are short with large muscles, while the distal segments are elongated with less musculature. In two of the major groups of ungulates, odd-toed and even-toed ungulates, what remain of