Equine Diseases Flashcards
High nail
When acute lameness appears within a few days of shoeing
- nail in sensitive tissues
Ringbone
Degenerative disease of pastern joint
- P1 and P2 have excessive movement
- severe arthritis in proximal interphalangeal joint
Stance phase
Foot is on the ground and limb is bearing weight
Swing phase
Limb is swinging forward prior to becoming weightbearing
Stride cycle
1 stance and 1 swing phase
- head goes down twice
Horse is lowest at ______
Mid-stance
Grade 0
Lameness not perceptible under any circumstances
Grade 1
Lameness difficult to observe
- not consistently apparent regardless of circumstances
Grade 2
Lameness difficult to observe at a walk to trot in a straight line
- consistently apparent under special circumstances (weight-carrying, circling, inclines)
Grade 3
Lameness consistently observable at a trot under all circumstances
Grade 4
Lameness obvious
- marked nodding, hitching, shortened stride
Grade 5
Lameness obvious
- minimal weight bearing in motion or at rest
Effusion
Increased synovial fluid
- secondary to inflammation in the joint
- trauma, DJD, OCD
Most common fractured carpal bone in a race horse
Distal radial bone
- followed by 3rd carpal bone
Sole pain at the toe
Toe bruise or laminitis
Pain over the central third of the frog
Navicular disease
Pain localized to the heel region
- corn
- heel abscess
- quarter crack
Degenerative joint disease
Arthritis or arthrosis
- deterioration of the articular cartilage
Sequence of nerve blocks
- palmar digital: navicular and sole
- palmar digital over the fetlock
- low palmar block: near buttons of the splint
- high palmar block: gets 2 palmar nerves, all soft tissues on the back of the leg and everything down
Conditions that produce Grade 5 nonweightbearing lameness
- fractures (P1-3, cannon, radius, humerus, scapula)
- infectious processes: septic arthritis, septic tendon sheath, cellulitis, sole abscess
- severe laminitis
- disruption of a tendon or ligament
Dimple
Place where articular cartilage did not form properly
Ankylosis
Stiffening and fusion of bones
- done to reduce pain
- seen with high load-low motion joints (pastern, distal tarsal)
Osteochondrosis
Failure or disruption of endochondral ossification
- defect on articular side of growth plate
Osteochondrosis dessicans
Formation of separate cartilage or osteochondral flap or fragment
Subchondral bone cyst
Defect in subchondral bone
Common OCD lesions
- distal intermediate ridge of tibia (DIRT)
- lateral trochlear ridge
Exercise and nutrition play roles as OCD ______
Disease modifier
Irregular/sporadic exercise has ______ risk compared to moderate/regular exercise
Increased
Deficiencies in _____, _____, and _____ may predispose to lesion formation
Copper, calcium, phosphorus
_____ is commonly the only sign in yearlings
Joint effusion
OCD lesions can occur in any joint, including ______
Articular faucets of the spine!
Predilection sites of the hock in order of frequency
- distal intermediate trochlear ridge of tibia
- lateral trochlear ridge of talus
- medial malleolus of tibia
- medial trochlear ridge of talus
Predilection sites of fetlock in order of frequency
- dorsal digital midsagittal ridge of MCP/MTP 3
- dorsal margin of P1
Predilection site of the stifle in order of frequency
- lateral trochlear ridge of femur
- medial trochlear ridge of femur
- distal patella
- intertrochlear groove
Lesions are likely permanent after:
- 5 months in fetlock and hock
- 8 months in stifle
All radiographically evident lesions are permanent after:
11 months
Multiple lesions
- stifle: 18-21% bilateral
- hock: 6-`0%
- fetlock: bilateral or all 4 affected
- multiple lesions in 1 joint, but uncommon to have multiple joints affected
_____ will fill the fragment defect
Fibrocartilage
- cannot regrow articular cartilage!!
How do subchondral cystic lesions differ from OCD?
- causes lameness, or effusion
- occur in any joint
- diagnose with nerve/joint blocks and radiographs (sclerotic rim)
Common site for subchondral cystic lesions
- medial femoral condyle (concurrent with medial meniscal injury)
- phalanges, carpal bones
Most common cause of lameness?
Navicular disease!
Equine navicular syndrome
Chronic, progressive disease affecting the navicular bone, navicular bursa, DDFT and associated soft tissue structures of the navicular apparatus
_____ border has foramena lined with synovium
Distal
_____ surface is common for problems
Palmar flexor
- covered by fibrocartilage, smooth surface for DDFT
Enthesiophyte formation is seen with
Suspensory and impar ligaments
- radiographic sign of navicular dz
What is the #1 risk factor for navicular dz?
Long toe, low heel
Hoof testing navicular dz
- positive response across frog and across heels
Disadvantages of radiographs
Does not allow evaluation of soft tissue structures
bone changes w/ navicular dz happen in end stages, can diagnose earlier
When trying to see changes in flexor surface, take a ______
45 degree PP-PD oblique
- navicular skyline
- loss of corticomedullary distinction (earliest sign) and sclerosis
Fractures of navicular bone can occur ______ navicular disease
Without
Most common lesion of navicular bone is _____
Deep digital flexor surface lesion
Medications in the ______ will freely diffuse to the navicular joint
Coffin joint
Palmar digital neurectomy
Desensitizes heel and sole
- only lasts 6 months to 2 years
Factors affecting tendon sheath prognosis
- which tendon is affected (flexor tendon has worse prognosis)
- infection
- chronicity
- if the sheath is involved
Flexor tendon laceration 7 weeks post surgery
Apply elevated heel-fetlock sling support shoe after granulation tissue fills wound
- gradually lower heel height
Femoropatellar joint sac communicates with ______
- medial femorotibial 80%
- lateral femorotibial 20%
- medial and lateral femorotibial do not communicate *
OCD fragment lesions often cause ______
Effusion
Fibularis tertius rupture has ____ prognosis
Good
- when horse stands, ends come together
- seen in horses recovering from full leg cast
Unable to extend hock =
Superficial digital flexor/gastrocnemius rupture
- prognosis fair in foals and grave in adults
Upward fixation of patella
Leg locks in extension
- due to laxity or stretching of middle/medial patellar ligaments
Stringhalt
Hyperflexion of hindlimb as each stride is iniitated
- faulty input from stretch receptors in lateral digital extensory
- secondary to scarring of lateral extensor tendon sheath
- trauma to dorsal MT3
- ingestion of Hypochoeris radicata
Fibrotic myopathy
Hindlimb hovers and then slaps ground caudally
- affects semitendinosus and fascia
- limited stifle extension
Bone spavin
DJD of distal intertarsal and tarsometatarsal joints
- bony swelling of distal medial tarsus
Bog spavin
Effusion of tibiotarsal joint
- young horses with OCD
Curb
Inflammation of long plantar ligament
- seen in horses with sickle hock formation
Thoroughpin
Effusion of tarsal sheath
- not uniform due to flexor retinaculum
