Unsoundnesses

Anastasia Kellogg

Unsoundness• An unsoundness is any

abnormality which interferes with a horse’s usefulness

• A lameness is an unsoundness that negatively affects a horse’s way of going

• All lamenesses are unsoundnesses but not all unsoundnesses are lamenesses (for example, a bowed tendon is both an unsoundness and a lameness, but moon blindness is only an unsoundness)

Unsoundness• A blemish does not affect a horse’s

usefulness, but affects his appearance, such as an old injury that has healed but is still visible (i.e. splints)

• Lameness may be caused by any combination of the following– Poor conformation (causes

predisposition)– Trauma (a direct blow, fall, sprain,

etc.)Poor hoof care

– Nutritional problems (including obesity)

– Nervous system and inner ear disorders

– Fatigue

Unsoundness

• The two main classifications of lameness are supporting leg lameness and swinging leg lameness

• Supporting leg lameness is visible when the horse places weight on the affected leg

• Swinging leg lameness is visible when the horse is in motion, particularly when he attempts to raise the affected leg

Unsoundness

• Some lamenesses may show both supporting and swinging symptoms

• Complimentary lameness results from the additional strain put on a sound leg when a horse is lame

• Concussion refers to the stress placed on a horse’s legs when he is worked on hard surfaces, and is often responsible for splints, ringbone, and bone spavins

Identifying Lameness

• When looking for the cause of lameness, look for any obvious causes, such as puncture wounds, check the feet and legs for hear, and watch the horse in motion

• Generally, when a horse is lame in a foreleg, his head will come up when the lame foot hits the ground, and his head will nod downward when the sound foot hits the ground

Identifying Lameness• Generally, when a horse is

lame in a hind leg, his head will nod downward when the lame foot hits the ground, and his head will come up when the sound legs hits the ground

• A horse’s hoof normally hits the ground heel first, and if he lands on his toes, his heel is probably sore (i.e. navicular)

• Most horses rest a hind foot while standing, and if they rest a forefoot it is usually a sign of trouble

Identifying Lameness• Resting a forefoot by placing it

well in front of the other is referred to as pointing

• Lightly tapping the hoof with a hammer and listening for hollow sounds can help locate an abscess

• When checking the feet for heat, it is sometimes helpful to wet both hooves with a sponge and watch the water evaporate in order to determine if one hoof is really warmer than the other

Identifying Lameness

• Always check the horse’s hooves for cracks and sole bruises

• New sole bruises are red, while older ones are yellow

• Hoof testers are useful to detect if a horse’s sole and frog are sensitive to pressure

Specific Lamenesses• Arthritis is the inflammation

of a joint– Any joint may be affected, but

the most common sights of arthritis are the fetlock, pastern, knee, shoulder, elbow, hock, stifle, and hip

– A major cause of arthritis is concussion, and other causes may include direct trauma and nutritional problems

– The three types of arthritis are• Serous arthritis• Chronic arthritis• Infectious Arthritis

Specific Lamenesses• The least serious type of

arthritis is serous arthritis• In a case of serous arthritis,

the swelling is caused by and increase in the volume of synovial fluid in the membrane surrounding a joint

• If corticoids are overused in treating serous arthritis, chronic arthritis often follows

• In chronic arthritis, the cartilage and bone are damaged permanently

Specific Lamenesses

• Chronic Arthritis is also known as osteoarthritis

• Infectious arthritis is serous arthritis complicated by an infection, usually in the bloodstream

• Navel ill is a form of infectious arthritis

Specific Lamenesses• Bursitis refers to the swelling of

a bursa, such as a tendon sheath• Joint mice are fragments of

bone and cartilage that accumulate on the border of a joint– The affected horse will be lame

when a “mouse” is caught in the joint, and sound when it works itself out of the joint

– Arthritis and chip fractures are the most common causes of joint mice

– With joint mice, surgery is almost always necessary

Specific Lamenesses• Fractures are breaks in a bone

caused by severe direct blows, bad falls, or severe stress and concussion– The three types of fractures are

• Simple• Compound• Greenstick

– A simple fracture is a clean break– A compound fracture breaks

through the skin– In a greenstick fracture, the bone

is bent and not completely broken; there is a splintering on the sides

Specific Lamenesses• Surgery is almost always

necessary to treat fractures• Both sprain and strain are

injuries caused by excessive force, and the words are often used interchangeably– Fatigue contributes to sprains– New sprains are puffy, swollen,

and painful, and sprains will not pit when pressed, as would a tenosynovitis

– Pressure bandaging, rest, and cold hosing are helpful immediately after injury, and hot packs may be used on an older injury

Specific Lamenesses• Bruises, properly called contusions, are injuries in which small blood vessels are broken in the skin, causing discoloration and soreness– In the horse, the most common

sight of a contusion is on the sole of the hoof, and is most commonly caused by the horse stepping on a stone

– Flat feet predispose a horse to sole bruises

– The horse’s sole is not supposed to bear weight, and if it is touching the ground corrective trimming and shoeing are needed

Specific Lamenesses• Sole bruises are treated by

soaking the horse’s foot, and sometimes using a hoof packing may help

• A new sole bruise will be red, and an older one will be yellow; if a sole bruise turns blue, and abscess may be developing

• Puncture wounds are wounds which are deeper than they are wide, and are dangerous since they form a home for bacteria, most notably clostridium tetani, which causes tetanus

Specific Lameness• Puncture wounds should be

kept clean, and should be made to heal from the inside out; if the surface grows closed over an unhealed puncture wound, a pocket of air will be trapped, leading to infection

• Sweeny is the atrophy (decrease in size) of the shoulder muscle due to nerve damage, and may be caused by a draft horse’s ill fitting collar or a severe direct blow to the shoulder

Specific Lamenesses• The muscle atrophy in

sweeny is caused by damage to the suprascapular nerve, which serves the supraspinatus and infraspinatus muscles

Specific Lamenesses• Bicipital Bursitis is an

inflammation of the bicipital bursa in front of the shoulder joint. It is caused by a blow at the point of the shoulder or a tearing of the tissue. A horse will show both swinging and supporting leg lameness, and may refuse to move forward, although he will still be willing to back up. The horse should be rested, and corticoids, used under veterinary instruction, may be helpful.

Specific Lamenesses

• Capped elbow or shoe boil is a bursitis of the olecranon process of the ulna, or the point of the elbow, caused by irritation– Capped elbow may be caused by the

horse’s shoe causing pressure to the elbow when the horse lies down, a severe direct blow to the elbow, a rider’s toe or stirrup iron repeatedly striking the elbow, or lying down on insufficient bedding

– Treatment for capped elbow includes removing the source of irritation, cold hosing, and astringents; a donut shaped boot may be fitted around the pastern to prevent the hoof from hitting the elbow

Specific Lamenesses

• Radial paralysis, or dropped elbow, is due to a paralysis of the radial nerve, the nerve which serves the extensors of the elbow, knee, fetlock, pastern, and coffin joints– Radial paralysis can be caused

by a kick to the humerus– The horse will stand with both

the knee and fetlock semiflexed, and will be unable to move the leg, dragging it when backed

Specific Lamenesses• Carpitis is an inflammation of

the knee; the affected knee will be hot, swollen, and hard, causing lameness– Rest and cold hosing may help

• Hygroma is a fluid filling in the knee

• Bowed tendon is a partial rupture of the deep or superficial flexor tendon and its sheath resulting from severe strain to one or both tendons, usually on the forelegs

Specific Lameness

• Bowed tendon is also known as tendosynovitis, tendonitis, or tendovaginitis

• Complete rest for up to a year, with cold water hosing and bandaging necessary in treatment

• Bucked shins, or metacarpal periostitis, is an inflammation of the periosteum (membrane around a bone) of the cannon bone

Specific Lamenesses• Bucked shins are caused by

concussion and/or overexertion

• Bucked shins almost always occur in both forelegs at once

• Young racehorses commonly suffer bucked shins

• A warm, painful swelling on the front of the cannon indicates bucked shins

• The horse will completely recover if rested

Specific Lameness

• Epiphysitis is an inflammation of the epiphysial, or growth, plates, in young horses, and is most commonly found at the distal end of the third metacarpal (lower cannon) or the distal end of the radius– The affected area will be

swollen and the horse will be lame

– Reduced dietary intake and rest are necessary

Specific Lameness• Constriction of the Volar or

Plantar Annular Ligament is a constriction of the volar, in front, or plantar, in back, annular ligament and superficial flexor tendon caused by a direct injury to the volar or plantar annular ligament– The symptoms include constant,

increasing lameness and a swelling and thickening of the superficial flexor tendon

– Surgery is the only treatment, and the ligament must be cut

Specific Lameness

• Ridge Lesion, found in the fetlock joint, is a wearing away at the cannon bone due to overflexation of the joint caused by overwork and poor shoeing; rest is a must

• Windpuffs are rounded swellings around the fetlock joint caused by concussion; the puffiness is a filling of synovial fluid

Specific Lameness• Osselets are osteophytes

which form in the anterior part of the fetlock joint, and are a type of trauma induced arthritis; osselets are sometimes called “little bones”– Osselets are common in race

horses, and other horses worked hard when young, and are caused by concussion

– Symptoms include lameness, heat, and swelling

– Rest is essential

Specific Lameness

• Sesamoiditis is the painful inflammation of the proximal sesamoids and the sesamoid sheath of the flexor tendon due to extreme strain on the fetlock, and is most common among hunters and race horses– Sesamoiditis is often

accompanied by windpuffs

Specific Lameness• Ringbone is a bony

enlargement, or calcium deposit, in the area of the pastern– High ringbone occurs near the

lower end of the first phalanx, while low ringbone occurs near the lower end of the second phalanx

– Ringbone may be either articular (involving a joint surface) or non articular; articular is more serious

– Rest, proper shoeing, and correction of nutrition problems are necessary

Contracted Heel

• Contracted Heel is caused by unnatural hoof lengths, a lack of frog pressure and weakening of the bars of the hoof– In contracted heels, the heel

of the hoof is actually visibly narrow, and the sole will be dished; the frog may also shrivel

– Corrective shoeing, soaking the feet, and rest will help, but recovery may take more than a year

Contracted Heel

• Contracted heel is most common in Saddlebreds, Tennessee Walkers, and Hackneys that have unnaturally long toes

• Contracted Tendons occur when the flexor tendons of the rear leg become shorter than the 3rd metatarsal (cannon bone) causing the fetlock to knuckle forward

Contracted Tendons

• Contracted tendons may be congenital (present at birth) or they may be acquired due to injury or a nutritional imbalance (vitamin A deficiency, vitamin D, calcium, phosphorus imbalance)

• Surgery and/or corrective shoeing are necessary

Sidebone

• Sidebone is the calcification of the lateral cartilages, beginning at the coffin bone and spreading outward– Sidebones are most

common in the front feet

– The outside lateral cartilage is usually the first to be affected

Sidebone

• Sidebones are difficult to detect at first; the horse may be lame, may land toe first, and may point when standing; the expansion of the hoof will be made difficult or impossible, and circulation will be effected, causing a chronic swelling below the knee

• Rest, cold therapy, and bute may all be used in treatment; the horse should be shod with pads

Scratches

• Scratches is a form of dermatitis of the pastern area, causing hair loss, scabiness, and general soreness of the area; washing and drying the area regularly will help to heal and prevent scratches [DON’T CONFUSE W/GRAVEL]

Scratches

• Scratches are often found when horses, especially standardbreds, are worked on a gravel track, and are then bathe without having their heels washed out; small stones and water collect in the area, causing irritation

Greasy Heel

• Greasy heel, sometimes called mud fever, is also a form of dermatitis of the pastern area, and is generally more severe; the pastern area will be inflamed, tender, and covered with a gray, greasy layer of scabs; excess hair should be clipped, and the area should be washed, dried, and treated with zinc oxide ointment

Greasy Heel

• Greasy heel is found in horses with long fetlock hair that are turned out in mud

Pedal Osteitis

• Pedal osteitis is an inflammation of the coffin bone causing general soreness and intermittent lameness– Pasture rest is

necessary, and when the horse returns to work, bar shoes are helpful

Navicular Disease

• Navicular disease is a degeneration of the distal sesamoid, or navicular, bone most commonly found in horses with upright pasterns, straight shoulders, and small feet– Both front feet are usually

affected by navicular, and therefore the horse may appear less lame than if one leg were affected; the horse will attempt to keep weight off his heels, landing on his toes and shuffling along

Navicular Disease• Using hoof testers to apply

pressure to the back of the frog will produce pain

• Navicular is incurable, but attempts should be made to reduce pressure on the navicular bone and bursa, as well as to reduce pain, by using anti-inflammatory drugs, and using shoes with rocker toes and leather pads will help

• A posterior digital neurectomy will stop pain

Thrush

• Thrush is a form of hoof rot, affecting the frog and clefts of the hoof– Thrush is caused by the

yeast Spherophourus necrophorus

– Symptoms of thrush include• Foul odor• Black gooey discharge

from clefts• Tenderness in frog• Lameness in severe cases

Thrush

• Treatment of thrush includes cleaning the hoof, disinfecting it, and applying a thrush remedy such as Kopertox or Thrush XX after the foot dries; an alternate method involves soaking the foot in bleach, but caution must be used not to get any on the coronary band or skin

Corns

• Corns are bruises found between the bars and wall of the hoof and involving both sensitive and insensitive structures– Corns are caused by poor

fitting shoes or shoes needing badly to be reset

– Correcting the shoeing error and soaking the foot is essential to treatment; infected areas should be treated with antiseptic; corrective shoeing may be necessary

Canker

• Canker is an inflammation of the frog of the hoof somewhat similar to thrush, although it is white rather than black and not as common– Canker can spread to the

sole, and is most common in draft horses with flat feet

– The effected foot should be kept clean and dry

Keratoma

• A Keratoma, or Horn Tumor, is a benign, cone shaped, tumor of hard horn in the toe which presses against the sensitive laminae causing lameness– A median neurectomy

(cutting the nerve that supplies the area) is the most effective treatment

Gravel• Gravel is a separation of the

white line, usually caused by a sharp object being driven into it; in severe cases the object may work its way up to the coronary band– The affected horse will be lame,

and there will be heat in the hoof/fetlock area; a black spot will be visible on the white line

– The affected area must be opened, drained, treated with iodine and bandaged; tetanus may follow if the horse is not up to date on vaccinations

Quittor• Quittor is a painful chronic

infection involving the lateral cartilage of the coffin bone; the cartilage becomes necrosed (dead) and drains through the coronary band, which happens to be the path of least resistance– Direct trauma is usually

responsible (quittor is relatively rare)

– Surgical removal of the dead cartilage, followed by bandaging, is necessary

Sandcracks• Sandcracks are cracks in the

hoof wall, usually beginning in the lower part of the hoof and splitting upwards toward the coronary band, where they cause the most damage– A sandcrack which runs

horizontally is called a cleft, and is usually caused by direct injury

– The hoof wall will not heal, and the sandcrack must be allowed to grow out; the crack itself should be closed in some way, such as sewing it shut, so that the new tissue doesn’t crack as it grows in

Quarter Crack

• A Quarter Crack is the most common and most severe type of crack in the hoof wall, since it is found on the inside of the front feet, where concussion is greatest

Seedy Toe

• Seedy Toe, or separation, is the destruction of the white line, most often in the toe, causing a cavity filled with dark colored material made up of dead tissue which may become infected– Symptoms include lameness

and a visible black mark in the white line

– Treatment includes disinfecting the area and padding the shoe

Hunter’s Bump• Sacroiliac Subluxation, or

Hunter’s Bumps, is a dislocation of the sacroiliac joint between the vertebral column and the pelvis, caused by torn ligament attachments due to stress– Hunter’s bumps are most

commonly seen in horses which participate in jumping sports (hunters, jumpers, steeplechasers and eventers)

– Symptoms of sacroiliac subluxation include the formation of a bump on the back above the area of the hip, shortened stride, and reluctance to jump

Hunter’s Bump

• Treatment includes rest, and perhaps an injection of an irritant into the area, causing scar tissue to form and immobilize the joint

Stifling• Upward fixation of the

patella, or luxation of the patella, is a stifle problem; the patella, or kneecap, catches on the trochlear process of the tibia when the horse is in motion, especially when turning– If the patella locks, the leg will

be extended straight backwards, and will be dragged if the horse is made to move; a slight movement of the patella will only produce a clicking sound as it strikes the tibia

Stifling• Once fixation has occurred

once, the ligaments in the area will be stretched, making a recurrence more likely

• To unlock a patella, place a lead line around the pastern and pull the foot forward; when the patella bulges, apply pressure to the top and back, clicking it into place, the horse will probably move as if nothing were wrong, but avoid tight turns

Stifling

• A desmotomy is a simple surgical procedure in which the medial patellar ligament is cut, preventing the patella from locking again

Gonitis

• Gonitis is a catch all term for stifle problems, including arthritis, sprains, cartilage degeneration, and fractures

Stringhalt

• Stringhalt is a nervous disorder in which the hind leg is jerked upward while the horse is in motion– Stringhalt is most

noticeable when turning or backing, and worsens in cold weather

– Surgery on the lateral extensor tendon may be effective

Thoroughpin

• Thoroughpin is a form of tenosynovitis in which the tarsal sheath of the flexor tendons is swollen due to the strain of the flexor tendons as they pass over the hock– Thoroughpin appears as a

movable swelling above the back of the hock

– On old thoroughpin is only a blemish, causing neither pain nor lameness

Thoroughpin

• Cold compresses, rest, and wrapping are helpful in a new case

Bog Spavin

• Bog Spavin is technically called a tarsal hyrathrosis– A bog spavin is a round,

movable swelling near the hock, specifically on the inner hock

– Bog spavins result from overwork, strain, concussion, and direct trauma

– A new bog spavin will be hot, and may cause lameness

– Cold applications and bandages will help a fresh bog spavin

Bog Spavin

• An old bog spavin will be a cold, painless, blemish

Bone Spavin

• Bone Spavin is a bony enlargement on the inner, lower hock, and is actually a form of osteoarthritis– A bone spavin is often

called a jack spavin– Cow hocks and sickle

hocks predispose a horse to bone spavins

– Bone spavins are caused by overwork of young horses, concussion, and mineral imbalance

Bone Spavin

• The bones involved in a bone spavin are the distal bone of the tarsus and the head of the cannon bone

Occult Spavin

• Occult Spavin is also a form of arthritis in the hock, but it is hidden and the horse may be lame for some time before it is visible

Occult Spavin

• The "flex test" is helpful in finding an occult spavin. The horse's hock is held in a flexed position for a minute, and then he is trotted immediately away. If an occult spavin is the cause of the lameness, the horse's lameness will be much worse immediately after the test

Capped Hock

• Capped Hock is a bursitis of the calcanean process of the fibular tarsal bone, or point of the hock, caused by a direct blow to the site of the injury– Capped hock rarely causes

lameness, but may be painful at first and could lead to curb

– Kicking a stall wall is a common cause of capped hock

Capped Hock

• Cold hosing and pressure bandages may help a new case

Curb

• Curb is a hard swelling four inches below the point of the hock resulting from a sprain or rupture of the plantar ligament– Cow hocks and sickle hocks

predispose a horse to curb– When a horse with curb walks,

his fetlocks may make a cracking noise

– Rest is necessary and shoeing the horse with a wedge

– Heeled shoes to allow the foot to slide is helpful

Unsoundnesses

• Systemic disorders which cause lameness include laminitis and azoturia

• Unsoundnesses which are not lamenesses include sight and hearing problems, poll evil, and fistulous withers

Poll Evil

• Poll Evil is a severe, pus filled swelling of the general area of the poll, accompanied by an infection of the bacteria Brucellus abortus

Fistulous Withers

• Fistulous withers is a severe, pus filled swelling of the withers, accompanied by an infection of the bacteria Brucellus abortus

• Both poll evil and fistulous withers may develop into huge open sores if not treated immediately

Unsoundness

• Both poll evil and fistulous withers may be caused by– A severe blow (hitting

the head on a low doorway or trailer ceiling)

– Excessively ill fitting tack (tight halter or low pommelled saddle)