1. Bag Of Bones or Good Structure: Skeletal Disorders

2. Lecture Objectives Define unsoundness. Define blemish.
For each disorder discussed, describe the cause, clinical signs, treatment and prevention.

3. 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

4. Unsoundness of the Head

5. 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

6. Overshot Jaw (parrot mouth)
Cause: genetics, trauma,
illness as foal nears period of
rapid growth
Clinical signs: maxillae
longer than mandible
Treatment: annual dental floating, surgical treatment
Prevention: not directly heritable

7. Blemishes of the Limbs

8. 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

9. 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

10. 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

11. 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

12. Blemish or Unsoundness of the Limbs

13. 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

14. 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

15. 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

16. Blemish and Unsoundness of the Limbs

17. 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

18. Bone Spavin Cause: sickle hock or shallow
hock joints around fine, round bone
Clinical signs: bony enlargement
at back or inside back border of
hock, at first lame only when
standing awhile
Treatment: use of NSAIDs, joint injections, surgical arthrodesis
Prevention: none

19. Bowed Tendon Cause: long toes, low heels, severe
strain, wear and tear with age,
relatively small tendons attached to
light round bone, inadequate
conditioning
Clinical signs: thickening of back
surface of leg above fetlock due to
tearing of superficial or deep flexor
tendon

20. Bowed Tendon Treatment: use of NSAIDs, use of
Surpass, hydrotherapy, hand
walking, injection with hyaluronic
acid, stem cell therapy, shock wave
therapy, exercise protocol
Prevention: proper conditioning
(sometimes)

21. 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, rough
in gaits, tends to stumble
Treatment: corrective trimming/
shoeing, cut the check ligament
Prevention: good nutrition (sometimes)

22. Contracted heel Cause: improper shoeing/trimming, hoof growth
Clinical signs: heel region narrower
than normal, small frog, concave
dished sole
Treatment: moisturize hooves,
promote expansion, corrective
shoeing (slipper shoes w/no >3
nails/branch
Prevention: proper hoof trimming

23. Curb Cause: sickle hocked, cow hocked
horses that slide too far, too fast in
deep ground, direct trauma
Clinical signs: enlargement on back
of leg just below hock due to plantar
ligament becoming inflamed/thickened,
pain, heat, swelling
Treatment: rest, hydrotherapy, joint
injection, oral, topical anti-inflamm.
Prevention: none

24. Fractures Cause: broken bone due to trauma Clinical signs:
Non weight-bearing lameness
Treatment: implant,
transfixation cast
Prevention: none

25. Laminitis Cause: excess carbohydrate
consumption, excessive concussion,
drugs, lush grass or legume pastures,
retained placenta
Clinical signs: inflammation of
sensitive laminae that attach hoof
to fleshy portion of foot, horse
walks on eggshells, foot warm to touch,
horse anxious, trembling, “points”

26. 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 overfeed
grain, expose to concussion,
limit grazing when grasses lush

27. Founder Cause: blood flow may cease, tissue may die, coffin bone
rotates downward, top of hoof
curls forward
Clinical signs: rings in hoof
wall, bruised soles or stone
bruises, widened white line
(seedy toe), dropped soles/
flat feet, thick cresty neck,
dished hooves

28. Founder Treatment: corrective trimming and shoeing, see laminitis
Prevention: prevent causes

29. Navicular Disease Cause: hard work, upright pasterns, small hooves,
large body, trimming heels
too low, trauma to bone
Clinical signs: damage to
navicular bursa or ligaments or deep
flexor tendon, lameness, may point

30. Navicular Disease
Treatment: corrective trimming/shoeing, injection of navicular bursa, NSAIDs, neurectomy
Prevention: maybe proper hoof care

31. Scratches Cause: natural skin oils lost to mud; cold, windy
weather; low humidity; frequent
bathing
Clinical signs: cracked, inflamed
skin and crusted scabs on horse’s
pastern
Treatment: trim hair, wash area,
remove scabs, dry, Vaseline, wrap
Prevention: keep out of mud

32. Sidebones Cause: forefeet of heavy horses
working on hard surfaces; frequent
in hunters/jumpers; due to repeated
concussion of quarters of feet;
improper shoeing, trauma
Clinical signs: loss of flexibility
of either/both lateral cartilages;
ossification; lameness; short stride;
may be exaggerated when walked
across a slope

33. Sidebones Treatment: corrective shoeing to promote expansion
of the quarters, use of NSAIDs,
use of pads
Prevention: none

34. Splints Cause: bench knees, hard training, trauma
Clinical signs: inflammation of the
interosseous ligament that holds
the splint bones to the cannon bone,
swelling, lameness in early stages at
trot or faster
Treatment: use of NSAIDs, rest,
hydrotherapy
Prevention: prevent causes if can

35. Stringhalt
Cause: lesions in the nerves, in US possibly due to sweet pea poisoning, in Australia, flat weed
Clinical signs: sudden lifting
or jerking upward of one or
both hind legs, most obvious with
first or second steps taken
Treatment: move away from
pasture, tenotomy of extensor
Prevention: avoid the plants above

36. Thrush Cause: abnormal hoof growth, improper trimming/shoeing,
poor diet, lack of use, chronic
lameness, 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/central
sulci

37. 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

38. Upward Fixation of the Patella
Cause: straight hocked conformation,
lack of fitness, excessive distal
patellar ligament length
Clinical signs: delay in flexion of the
limb, may prevent horse from flexing
stifle, mild pelvic limb asymmetry or
lameness

39. Upward Fixation of the Patella
Treatment: exercise, corrective shoeing, estrogen therapy, intraligamentous infusion of counterirritant, medial patellar
desmotomy
Prevention: conditioning, corrective
shoeing

40. 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.