Bag Of Bones or Good Structure: Skeletal Disorders

Lecture Objectives

Define unsoundness. Define blemish. For each disorder discussed,

describe the cause, clinical signs, treatment and prevention.

Defintions

Unsoundness – any alteration of a horse’s structure or any disease that lessens or is likely to lessen a horse’s working power

Blemish – any mark or deformity that diminishes the beauty or value of a horse but does not affect its usefulness

Unsoundness of the Head

Undershot Jaw (monkey or sow mouth)

Cause: inherited unsoundness that

results in the mandible being longer

than the maxillae Clinical signs: mandible longer

than maxillae Treatment: annual dental

floating Prevention: do not breed those

affected

Overshot Jaw (parrot mouth) Cause: genetics, trauma,illness as foal nears period ofrapid growth Clinical signs: maxillaelonger than mandible Treatment: annual dental

floating, surgical treatment Prevention: not directly

heritable

Blemishes of the Limbs

Capped elbow or shoe boil

Cause: usually injury from shoe when front leg is folded

Clinical signs: swelling at point

of elbow Treatment: hydrotherapy Prevention: none

Capped hock

Cause: bumping hock when transported in short trailer or one with unpadded tail gate

Clinical signs: thickening of skin or large callus at point of hock

Treatment: none Prevention: wrap legs, use padded

gate

Thoroughpin

Cause: young horses just starting training, horses in heavy work, horse with poor hindlimb conformation in the fetlock region

Clinical signs: fluid swelling of the deep digital flexor tendon as it passes around the hock

Treatment: none Prevention: none

Windpuffs, windgalls or road puffs

Cause: young horses just starting training, horses in heavy work, horse with poor hindlimb conformation in the fetlock region

Clinical signs: fluid swelling of the sheath of the deep digital flexor tendon or annular ligament in the ankle

Treatment: none Prevention: none

Blemish or Unsoundness of the Limbs

Hoof Cracks

Cause: hoof wall too long, horse kept in mud a lot, drawing moisture out of feet as mud dries

Clinical signs: crack in hoof, possible lameness

Treatment: treat as soon as notice, if extensive vet may need to remove crack area

Prevention: keep hooves moist

High Ringbone

Cause: aging, trauma, straight shoulders, upright pasterns, base narrow toe in or base wide toe out conformation, due to tearing and damage to tendons and ligaments

Clinical signs: bony enlargement at pastern joint

Treatment: rest, hydrotherapy, fuse joints

Prevention: none

Low Ringbone

Cause: aging, trauma, straight shoulders, upright pasterns, base narrow toe in or base wide toe out conformation, due to tearing and damage to tendons and ligaments

Clinical signs: bony enlargement at coffin joint

Treatment: rest, hydrotherapy, fuse joints

Prevention: none

Blemish and Unsoundness of the Limbs

Bog Spavin

Cause: horse trying to straighten hock, trauma such as quick stops, turns, getting kicked by another horse

Clinical signs: soft, fluctuating enlargement at tibiotarsal joint on hock due to distension of joint capsule

Treatment: joint injections, rest, controlled exercise

Prevention: none

Bone Spavin

Cause: sickle hock or shallowhock joints around fine, round

bone Clinical signs: bony enlargementat back or inside back border of hock, at first lame only whenstanding awhile Treatment: use of NSAIDs, joint

injections, surgical arthrodesis Prevention: none

Bowed Tendon

Cause: long toes, low heels, severe strain, wear and tear with age,relatively small tendons attached tolight round bone, inadequateconditioning Clinical signs: thickening of backsurface of leg above fetlock due totearing of superficial or deep flexortendon

Bowed Tendon

Treatment: use of NSAIDs, use ofSurpass, hydrotherapy, hand walking, injection with hyaluronicacid, stem cell therapy, shock wavetherapy, exercise protocol Prevention: proper conditioning(sometimes)

Club foot

Cause: contracted deep digital flexor

tendon, injury (one hoof), improper nutrition (2 or more), or hereditary Clinical signs: hoof axis too

straight,hoof too upright, horse is stiff,

roughin gaits, tends to stumble Treatment: corrective trimming/shoeing, cut the check ligament Prevention: good nutrition

(sometimes)

Contracted heel

Cause: improper shoeing/trimming, hoof growth

Clinical signs: heel region narrower

than normal, small frog, concavedished sole Treatment: moisturize hooves, promote expansion, correctiveshoeing (slipper shoes w/no >3nails/branch Prevention: proper hoof trimming

Curb

Cause: sickle hocked, cow hocked

horses that slide too far, too fast in deep ground, direct trauma Clinical signs: enlargement on

backof leg just below hock due to

plantarligament becoming

inflamed/thickened,pain, heat, swelling Treatment: rest, hydrotherapy,

jointinjection, oral, topical anti-

inflamm. Prevention: none

Fractures

Cause: broken bonedue to trauma Clinical signs:Non weight-bearing lameness Treatment: implant, transfixation cast Prevention: none

Laminitis

Cause: excess carbohydrateconsumption, excessive

concussion,drugs, lush grass or legume

pastures, retained placenta Clinical signs: inflammation of sensitive laminae that attach hoofto fleshy portion of foot, horsewalks on eggshells, foot warm to

touch,horse anxious, trembling, “points”

Laminitis

Treatment: stand horse in ice water,

diagnose/treat primary problem, vasodilators, anti-coagulants, anti-endotoxins, stable on soft ground, pad feet Prevention: do not overfeedgrain, expose to concussion, limit grazing when grasses lush

Founder

Cause: blood flow may cease,tissue may die, coffin bonerotates downward, top of hoofcurls forward Clinical signs: rings in hoofwall, bruised soles or stonebruises, widened white line(seedy toe), dropped soles/flat feet, thick cresty neck, dished hooves

Founder

Treatment: corrective trimming and shoeing, see

laminitis Prevention: prevent causes

Navicular Disease

Cause: hard work, upright pasterns, small hooves, large body, trimming heelstoo low, trauma to bone Clinical signs: damage to navicular bursa or ligaments or

deepflexor tendon, lameness, may

point

Navicular Disease

Treatment: corrective trimming/shoeing, injection of navicular bursa, NSAIDs, neurectomy

Prevention: maybe proper hoof care

Scratches

Cause: natural skin oils lost to mud; cold, windyweather; low humidity; frequentbathing Clinical signs: cracked, inflamedskin and crusted scabs on horse’s pastern Treatment: trim hair, wash area,remove scabs, dry, Vaseline, wrap Prevention: keep out of mud

Sidebones Cause: forefeet of heavy horsesworking on hard surfaces; frequentin hunters/jumpers; due to

repeatedconcussion of quarters of feet;improper shoeing, trauma Clinical signs: loss of flexibilityof either/both lateral cartilages;ossification; lameness; short

stride;may be exaggerated when walked across a slope

Sidebones

Treatment: corrective shoeing to promote expansionof the quarters, use of NSAIDs, use of pads Prevention: none

Splints

Cause: bench knees, hard training,

trauma Clinical signs: inflammation of

the interosseous ligament that holdsthe splint bones to the cannon

bone, swelling, lameness in early stages

attrot or faster Treatment: use of NSAIDs, rest,hydrotherapy Prevention: prevent causes if can

Stringhalt

Cause: lesions in the nerves, in US possibly due to sweet pea poisoning, in Australia, flat weed

Clinical signs: sudden liftingor jerking upward of one or both hind legs, most obvious withfirst or second steps taken Treatment: move away frompasture, tenotomy of extensor Prevention: avoid the plants

above

Thrush

Cause: abnormal hoof growth,improper trimming/shoeing,poor diet, lack of use, chroniclameness, poor circulation to frog,horses with deep sulci (clefts in

foot) Clinical signs: thick, black putty

like,foul-smelling degenerative

material on and in the frog and

collateral/centralsulci

Thrush

Treatment: have farrier trim away dead, infected tissue;

provide regular exercise to stimulate the

frog, identify/correct underlying cause

of infection, pick, clean and medicate

the affected foot/feet at least daily Prevention: pick, clean, inspect

each foot daily, regular

turnout/exercise, avoid overagressive hoof pick use

Upward Fixation of the Patella

Cause: straight hocked conformation,

lack of fitness, excessive distalpatellar ligament length Clinical signs: delay in flexion of

the limb, may prevent horse from

flexing stifle, mild pelvic limb asymmetry

orlameness

Upward Fixation of the Patella

Treatment: exercise, corrective shoeing, estrogen therapy, intraligamentous infusion of counterirritant, medial patellar

desmotomy Prevention: conditioning,

correctiveshoeing

Lecture Objectives

Define unsoundness. Describe unsoundness of the

head related to the skeletal system.

Define blemish. Describe blemishes of the limbs

related to the skeletal system. Describe unsoundness of the

limbs.