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166 Cards in this Set
- Front
- Back
What radiographs are routinely taken when radiographing the equine forelimb?
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1) Dorsal-palmar/plantar
2) Lateromedial 3,4) two obliques below the tibia |
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What radiographic views are usually taken of the equine stifle?
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1) Caudal-cranial
2) Lateromedial 3) Caudolateral-Craniomedial |
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True or false. It is best to use the fastest film-screen system as possible when radiographing horses.
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False! Maximize the detail by using the slowest film-screen system possible
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What type of animal preparation has to be done before radiographing the equine limb?
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Dry clean hear coat
Remove shoes Pack sulci |
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What is the routine way to view a film?
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Head and lateral to the left
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How do you view a skyline radiograph?
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As the x-ray machine "views" it
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What type of radiographic exposure do you want when radiographing the equine forelimb?
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Adequate to see bone detail, but still preserve visibility of soft tissue
-Make sure portable x-ray tube is proper distance from the cassette |
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True or false. Radiologists do not want to see the white borders around your film (collimation).
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yes, they do, a lot more radiation exposure in large animal as it is
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What safety gear do you wear when shooting equine radiographs?
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Lead gloves and apron
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What are 3 radiation safety practices?
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1) Wear lead gloves & apron
2) Collimate 3) Cassette holders and tripod for x-ray tube |
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Where are markers placed on radiographs?
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R & L markers are always placed laterally, or in the lateral view dorsally
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What are the 7 classifications of equine bone diseases?
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1) Acute injury
2) Chronic repetitive trauma 3) Degenerative joint disease 4) Infection 5) Metabolic bone disease 6) Immune mediated joint disease 7) Neoplastic disease |
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How does the distal phalanx normally appear on an equine radiograph?
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P3 is parallel to the dorsal hoof wall
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Where should the center of the beam be located when taking a radiograph of the distal phalanx of a horse?
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Center of the beam should be on the coronary band
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Where do you want to put the cassette when radiographing the equine distal phalanx?
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On the medial aspect as close as possible
-increase distance from cassette then get magnification |
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What area on the distal phalanx of the horse can be seen well with a horizontal dorsopalmar view?
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The conformation of the solar margin-are there any angles? + joints should all be lined up
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How do you shoot a dorso 45 proximal-palmarodistal view of the equine distal phalanx?
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Put the cassette in a tunnel and put the foot on top of it
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What part of the hoof can be evaluated using a dorso 45 proximal-palmarodistal oblique?
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Can see the entire solar margin and can evaluate the vascular markings and crena (A shallow notch in the dorsal solar margin of the distal phalanx P3)
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How should the vascular markings in the hoof appear?
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Should all be fairly parallel -can compare left and right
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How can you tell the difference b/w the front and rear equine distal phalanx?
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Rear is more pointy
Front is rounded |
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What does it usually mean when a horse has a hoof-pedal alignment problem? How else can you check?
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Laminitis, can also use hoof tester hit the bottom of the hoof where P3 is located laminitis will be painful
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What is laminitis?
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Separation of the hoof layers
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What causes laminitis?
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Incredible range of things: first time out in spring pasture, repetitive trauma, pharmaceuticals
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What happens as laminitis progresses?
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P3 can rotate until punctures through the solar surface of the hoof.
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How can you check the hoof-pedal alignment on a radiograph?
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Draw a line from coronoid band to extensor process (a) and a line from dorsal aspect of distal P3 to the caudal aspect proximal P3 (b) and if a/b=<0.265 then hoof is normal, if higher than =rotation=laminitis
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What does it mean when there's gas in the hoof wall?
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Means there's gas-forming bacteria in the hoof wall, could be an abscess of perforating wound-both need attention
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What happens to the solar margins in a horse w/ laminitis?
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Edges will get fuzzy because P3 applies more weight dorsally
Chronic changes can result in new bone formation |
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What do you see on a radiograph of chronic pedal osteitis?
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-Vascular canals are wider
-Demineralization-either diffuse or focal -Diffuse roughening & irregular margin of solar border of P3 |
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How does scintigraphy work?
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Inject radiopharmaceutical I.V. (vascular=phase I) and binds to soft tissues (phase II) and bone (phase III) hydroxyapatite
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What does scintagraphy show you?
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Shows where there's increased bone activity-like increased uptake and periosteal response bc of trauma
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True or false. Scintigraphy works well for evaluating the distal limb.
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True
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What is pedal osteitis?
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demineralization of the third phalanx as the result of inflammation
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Why is osteomyelitis not a very good term for inflammation in the third phalanx?
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because the third phalanx doesn't have a medulla and cortex like other bone
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What is different about the periosteum of P3?
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Doesn't have a uniform periosteal coating like other bones, has periosteum on proximal and dorsal aspect, but distal part is not covered as much
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If a phalanx undergoes repetitive trauma and develop inflammation, is this considered osteomyelitis?
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No, because it's an adaptation to repetitive trauma, not an active inflammatory process-this is pedal osteitis
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How can you visualize the medial palmar arteries? Why would you want to do this?
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Perform an angiogram
-One way to look for laminitis, which has a marked decrease in perfusion of the corium (lack of blood flow through circumflex artery) |
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Why would IV injection of antibiotics not work well for an infection in the corium?
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Has low vasculature so wouldn't establish very high concentrations
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What is a side bone?
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Ossification of the ungular cartilage- extra ossification on the palmar process.
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Can the side bone fracture?
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Yes, has a separate center of ossification and can fracture; can also get inflammation of side bones
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Ultrasound of the phalanx can be difficult because the horn can't be penetrated, what can you do for better visualization of the phalanx?
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Trim down a mm or 2 in frog, then soak the hoof over night
-Now done more w/ CT or MRI |
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What is a buttress foot?
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Extensor process fracture that heals with a callus that is extremely high and extends forward
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What causes a buttress foot?
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Secondary to traumatic periostitis or avulsion fracture of the extensor process
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True or false. Distal phalanx "cysts" are pretty common.
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False, not very common
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What are 3 differential diagnoses of a distal phalanx "cyst"?
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1) Bone abscess
2) Osteochondrosis 3) Keratoma |
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What do keratomas look like on a radiograph?
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Like someone shot a hole through the phalanx
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What is a keratoma?
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Abnormal mass of squamous epithelial cells with abundant keratin and granulation tissue.
-Can include inflammatory cells |
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True or false. Keratomas develop slowly over a period of time.
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True
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What is quittor?
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Chronic infection/necrosis of the ungular cartilage (on end of palmar process)
-e.g. have a perforating wound then get inflammatory process and get osteomyelitis then over time get quittor |
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Quittor used to be common in what horses?
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Working draft horses
-Don't see much anymore |
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What usually causes quittor?
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Usually secondary to an injury
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How does the X-ray beam have to hit the film to be able to see a fracture?
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Has to be parallel to fracture
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What will you see to indicate a chronic solar margin fracture?
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Bone remodeling on the solar margin
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What does a dorsal 60 degree proximal 45 degree lateral-to-palmarodistomedial oblique of the distal phalanx allow visualization of?
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Lateral aspect of navicular bone
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What does it usually mean if the navicular bone is elongated?
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The navicular bone is remodeling
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What view allows evaluation of the flexor surface of the navicular bone?
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Palmaroproximal to palmarodistal (flexor view)
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What is different about taking a 60 degree dorsopalmar view that's trying to visualize the navicular bone instead of P3?
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Come from higher than would for P3 and put navicular bone at center
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What are the 2 benefits of using a grid with a dorsopalmar view of the navicular bone?
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1) More contrast
2) Less blurring of margins, trabecular pattern |
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What are the 7 signs of navicular syndrome?
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1) Increased numbers & size of synovial channels (VS nutrient foramen)
2) Lysis of flexor cortex 3) "Cyst" formation 4) Sclerosis 5) Enthesophyte formation 6) Osteophyte formation 7) Fracture, ligament mineralization, |
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True or false. The navicular bone has a separate center of ossification.
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True
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What is the biggest impact of navicular syndrome?
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Quickly changes the value of the horse and what it can be used for
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Why is lysis of the flexor cortex of the navicular bone such a significant lesion?
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Because the deep digital flexor tendon runs over the flexor cortex so if its an uneven surface then it scratches and will get lesions in the tendon
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What does it mean if there are "lollipop" like lesions on the navicular bone?
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"consistent with" navicular syndrome
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What does it mean if you see large lollipops and enthesophytes on the navicular bone?
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Pretty consistent with navicular syndrome
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True or false. Scintigraphy can be used to identify navicular bone degeneration.
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True
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What fracture of the navicular bone is hardest to diagnose?
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Distal flexor border fractures-look at medial and lateral borders of distal borders of navicular bone
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What can you do to better visualize the distal interphalangeal joint with only radiography available?
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Do arthrography-inject water soluble organic iodine- contrast agent; administer either IV or intrathecal (into or occurring in the space under the arachnoid membrane of the brain or spinal cord.)
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What are 3 lesions you can look for on a radiograph of the forelimb foot that is indicative of degenerative joint disease?
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1) Osteophytes (periarticular & look for lesion opposite on other bone)
2) Irregular joint space or malalignment 3) Subchondral sclerosis |
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What is the most common site of periarticular osteophyte formation due to DJD on the phalanx?
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Extensor process
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Why do you take a radiograph of a deep digital flexor contracture (club foot)?
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To rule out osseous lesions as the cause
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When do we most commonly see DDF contracture? What can be done?
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-In younger animals (foals) bc get folded up in uterus
-they often can't get up so have to help get them up so can stretch out their legs |
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How will a horse present if it has a distal interphalangeal joint luxation?
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Will be walking on middle phalanx
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Compare a luxation and subluxation?
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Subluxation=particular contact w/ articular surfaces
Luxation=no contact |
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How can you distinguish between a contracted deep digital flexor and superficial digital flexor?
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SDF will cause deformity of proximal interphalangeal joint, also DDF contracture will cause P3 to be pulled back so P1, P2 and P3 are no longer straight and aligned
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What ligament connects the proximal and distal sesamoid bones to the proximal and middle phalanx of the equine forelimb?
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Distal sesamoidean ligament
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What part of the equine forelimb is affected by osteochondrosis?
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Articular cartilage (can affect epiphyseal growth plate)
Physis (metaphyseal growth plate) |
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What is the pathogenesis of osteoarthrosis?
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cartilage gets thicker so not as supported by vasculature bc too thick so area further away from vasculature gets necrotic and starts to chip off and die off, also thickening has different density so predisposed to fissures
-Focal cartilage hypertrophy---> basal cartilage layer necrosis---> stress induced fissures--> healing or osteochondral fracture |
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What are the 2 possible outcomes of a defect in endochondral ossification?
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1) Cartilage Separation= Osteochondritis dessicans
2) Retention of cartilage= Subchondral bone cyst |
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What are the 4 factors that predispose an animal to osteochondrosis?
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1) Rapid growth
2) Genetic predisposition 3) Nutritional excess/imbalance 4) Intrinsic factors -Glucocorticoid/parathyroid hormone -Vitamin D -Site vulnerability/predilection (trauma?) |
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What are the 3 patterns of articular osteochondrosis?
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1) Cartilage fissures/flaps
2) Osseous cyst-like lesions (subchondral cystic lesions "cystoids") 3) osseous bodies/separate centers of ossification (joint mice) |
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What are 5 common abnormal findings in ruminant and pseudoruminant forelimbs?
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1) DJD
2) Septic arthritis 3) Osteomyelitis 4) Trauma 5) Metabolic disease |
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What view is good for looking at lesions on the distal aspect of the proximal sesamoids of the equine forelimb?
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Dorsal 10 degree proximal 45 degree lateral -palmaromedial
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When does the distal growth plate of metacarpal 3 close in horses?
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8-12 months
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When does the proximal growth plate of the proximal phalanx of the equine forelimb close?
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6-9 months
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When does the distal growth plate of the proximal phalanx of the equine forelimb close?
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6-9 months
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What are 6 lesions related to degenerative joint disease?
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1) Soft tissue swelling
2) Osteophyte and enthesophyte formation 3) Joint space narrowing 4) Subchondral sclerosis 5) Subchondral lysis w/ cyst formation 6) Osteochondromas, joint mice |
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What are 3 ways that DJD causes soft tissue swelling?
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1) Joint effusion
2) Joint capsular proliferation 3) Proliferation of surrounding periarticular tissues |
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What are 2 common locations for soft tissue swelling from DJD in the fetlock?
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1) dorsal side
2) palmar/plantar surface just proximal of proximal sesamoid bones |
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What are 2 common areas of osteophyte formation from DJD in the fetlock?
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1) Dorsal, proximal aspect of P1
2) Elongation of proximal sesamoid bone (looks like a nose) |
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What is villonodular synovitis?
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Nodular proliferation of the joint capsule adjacent to the dorsoproximal limit of the sagittal ridge of metacarpal 3
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What are 6 lesions related to degenerative joint disease?
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1) Soft tissue swelling
2) Osteophyte and enthesophyte formation 3) Joint space narrowing 4) Subchondral sclerosis 5) Subchondral lysis w/ cyst formation 6) Osteochondromas, joint mice |
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What are 3 ways that DJD causes soft tissue swelling?
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1) Joint effusion
2) Joint capsular proliferation 3) Proliferation of surrounding periarticular tissues |
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What are 2 common locations for soft tissue swelling from DJD in the fetlock?
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1) dorsal side
2) palmar/plantar surface just proximal of proximal sesamoid bones |
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What are 2 common areas of osteophyte formation from DJD in the fetlock?
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1) Dorsal, proximal aspect of P1
2) Elongation of proximal sesamoid bone (looks like a nose) |
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What is villonodular synovitis?
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Nodular proliferation of the joint capsule adjacent to the dorsoproximal limit of the sagittal ridge of metacarpal 3
-With adjacent erosion of MC3 -Nodules may calcify or ossify |
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What is the best way to diagnose villonodular synovitis?
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Arthrogram-won't get contrast in all of joint capsule bc there's thickening of synovium
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Where do we commonly see osteochondral flap or cyst formation with osteochondrosis in the fetlock?
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Dorsal sagittal ridge of MC3
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Where will we see subchondral cysts with osteochondrosis in the fetlock?
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Weight bearing areas
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Where do osteochondral fragments form from osteochondrosis in the distal limb?
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Plantar proximal margin of proximal P1
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What's worse an articulate or non-articulate osteochondral fragment?
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Articulate, much more likely to develop DJD
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What are 2 types of osteochondral fragments?
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Type I: articular
Type II: non-articular |
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What are 4 possible changes in osteology that can occur with septic arthritis?
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1) Periarticular soft tissue swelling
2) Osteolysis 3) Malalignment, subluxation or collapse of the joint 4) Periosteal proliferation at the joint margins |
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Why does the joint width seem increased with an unweighted radiograph of septic arthritis sometimes?
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Increased joint fluid may increase joint width in unweighted radiographic exam
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What are 2 radiographic lesions characteristic of sesamoiditis?
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1) Bony proliferation of nonarticular surfaces of sesamoid
2) Linear or cystic lysis in abaxial (away from axis) region |
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What other condition is sesamoiditis commonly associated with?
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Usually a degenerative disease associated w/ suspensory branch desmitis (inflammation of a ligament) because medial and lateral branches of suspensory ligament insert on proximal sesamoid
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What does it mean if the sesamoid is deviating towards the abaxial surface?
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Could be axial sesamoiditis (horse will present as very lame)
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How does intersesamoidean desmitis present on a radiograph?
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Erosion of the axial surface (s) of the proximal sesamoid bones
-Can be both sides or unilateral -May be septic or non-septic |
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What is it called when the distal aspect of the proximal sesamoid is fractured?
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Basilar sesamoid fracture
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True or false. Horses don't have a first carpal bone.
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False, some horses don't but some do
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When does the distal radial epiphysis of the equine forelimb close?
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20 mo - 30 mo
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What carpal bones make up the proximal row of carpal bones?
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Radial, intermediate, ulnar carpal bones
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When does the accessory carpal bone apophysis close?
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5-7 months
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What bones comprise the distal carpal row?
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Second (first), third, fourth carpal bones
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What metacarpal bones do horses have?
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second (splint bone), third, fourth (splint bone)
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Compare an apophysis and physis.
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Usually where have ligaments and tendon insert=apophysis, whereas physis=long bones where have growth plate
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What joints make up the carpus?
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Radiocarpal joint (separate)
Middle carpal joint Carpometacarpal joint |
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True or false. Accessory carpal bone is located medial.
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False, laterally located
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What does the accessory carpal bone superimpose with on a dorsal palmar?
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Ulnar carpal bone (laterally located)
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Which carpal bone comprises the majority of the distal row of carpal bones (i.e. which one takes up the most space)?
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Third carpal bone
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On a lateral view of the carpus does the border of the ulnar carpal bone or radial carpal bone extend further dorsally?
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Ulnar carpal bone
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How can the location of soft tissue swelling in the carpus be differentiated?
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By identification of synovial fat pads located in the radiocarpal joint and extensor carpi radialis tendon
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What do you call it if the fat pads of the carpus are obliterated?
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Cellulitis: diffuse soft tissue swelling that is not purely localized to region of the carpus and affects the limb circumferentially.
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What does it mean if the dorsal aspect of the fat pad is compressed?
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Something outside of the joint capsule is compressing it
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How can you tell the difference b/w an acute and chronic fracture?
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Acute: nice sharp margins
Chronic: can see bone remodeling happening |
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Why is it worse to have a fracture in the grooves of the distal radius?
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Because the common digital extensor tendon and extensor carpi radialis tendon pass over these grooves
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What carpal bone fractures most commonly in horses?
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Dorsal surface of 3rd carpal bone, thought to be due to stress
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True or false. Comminution is common with fractures of the accessory carpal bone.
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True
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How long does it take fractures of the accessory carpal bone to heal?
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Minimum of 6-9 months
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How do accessory carpal bone fractures heal?
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Often by a fibrous union
-Signs of carpal tunnel pain and swelling may persist |
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What causes osteochondrosis?
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May be a defect in endochondral ossification, but may also arise from focal trauma, osteomyelitis or septic arthritis
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Where does incidental osteochondrosis usually occur?
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Small size and nonarticular locations
-**Ulnar carpal bone -Also radial, accessory, second and fourth carpal bones |
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Osteochondrosis in a bone can predisopose the area to what?
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Potential for secondary fracture or DJD when articular
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Where does incidental osteochondrosis usually occur?
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Small size and nonarticular locations
-**Ulnar carpal bone -Also radial, accessory, second and fourth carpal bones |
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What type of lesions are common with osteochondrosis?
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Cyst-like lesions
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Osteochondrosis in a bone can predisopose the area to what?
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Potential for secondary fracture or DJD when articular
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What animals get physitis?
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Immature rapidly growing horses
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What type of lesions are common with osteochondrosis?
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Cyst-like lesions
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What are 5 radiographic characteristics of physitis of the forelimb?
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1) Distal radial physis is assymetrically widened, may affect other open growth plates
2) Adjacent trabecular bone is sclerotic 3) Metaphyseal and epiphyseal flaring 4) Periosteal reaction 5) Surrounding soft tissue swelling |
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What animals get physitis?
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Immature rapidly growing horses
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What are 5 radiographic characteristics of physitis of the forelimb?
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1) Distal radial physis is assymetrically widened, may affect other open growth plates
2) Adjacent trabecular bone is sclerotic 3) Metaphyseal and epiphyseal flaring 4) Periosteal reaction 5) Surrounding soft tissue swelling |
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What deformity can be associated with physitis?
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Asymmetric growth plate closure---> carpal varus (legs twisted medially)
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What is flaring?
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Means the bone widens towards the physis
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What are 2 diseases that cause widening of the physis and metaphyseal flaring?
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1) Physitis
2) Ricketts |
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What 2 things will you see on a radiograph of an animal with osteomyelitis and septic arthritis of the carpus?
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1) soft tissue swelling (perilesional or articular)
2) Osteolysis w/ poor margination when acute, sclerotic margin when chronic |
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In foals, where will osteomyelitis and septic arthritis center on in the carpus?
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Metaphysis, physis, epiphysis or joint
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Osteomyelitis and septic arthritis will occur secondary to what 3 things?
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1) Hematogenous ('navel ill')
2) Extension from adjacent soft tissues 3) Trauma |
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What is a lesion that is very characteristic of septic arthritis?
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Dramatic soft tissue swelling
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What determines the degree of significance of DJD?
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Whether the joint is highly motile or not, highly motile joints such as proximal intercarpal joint are more significant, but distal intercarpal joint isn't as high motion so it's not as significant
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What 2 things does bone dysmaturity include?
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Bone hypoplasia & immaturity
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What are 5 radiographic findings of bone dysmaturity?
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1) Cuboidal bones are small and rounded (look like fetal bones)
2) Space b/w ossification centers is increased bc of larger cartilage surrounding it 3) Ossification centers may be stippled rather than homogeneous 4) Abnormal shape from crushing 5) Angular limb deformity may develop |
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What are 3 carpal angular limb deformities?
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1) Radial malformation
2) Carpal malformation 3) Metacarpal malformation |
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What are the 3 regions of radial malformations?
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1) Epiphyseal
2) Metaphyseal 3) Diaphyseal |
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What are the 3 carpal bone malformations that occur?
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1) Third carpal bone
2) Fourth carpal bone 3) Subluxated middle carpal joint |
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What are 2 metacarpal malformations?
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1) Displaced fourth metacarpal bone
2) Third metacarpal diaphyseal malformation |
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How can you detect angular limb deformities on radiographs?
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Use geometric analys:
-Draw vertical line that bisects long axis of long bones -Draw horizontal line at joints and physes |
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What is Ricketts? Radiographic evidence?
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Metabolic disease, where lack Vitamin D
-Widening of physis -Metaphyseal flaring |
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What type of fractures does Ricketts predispose an animal to?
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Folding fractures
|
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What is 'splint'?
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When have trauma to the splint bones
-see massive periosteal proliferation |
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When does 'splint' cause a problem?
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When the callus formation grows towards the inner surface because can compress the suspensory ligament
|
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Why are 'splints' easy to see radiographically?
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Massive periosteal proliferation!!!!!
|
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What horses is periostitis (bucked shins) common in?
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Athletic horses
|
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What causes periostitis? where does it usually occur?
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May occur secondary to trauma
Usually located over the dorsal to off-center of dorsal cortex (e.g. dorsal surface of MC 3 has little periosteum) |
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What usually causes MT2/MT4 and MC2/MC4 fractures?
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Direct blunt trauma
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What should you do if an animal has osteomyelitis of a splint bone?
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Treat because will keep getting worse and worse and can get secondary fractures
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Why are bone infarctions sometimes localized to the outer 1/3?
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Due to loss of periosteal blood supply
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When are bone infarctions the full thickness of the bone?
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Severe adjacent soft tissue or nutrient artery injury, soft tissue contamination
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How do you proceed when you see a bone sequestrum?
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Surgically intervene bc a sequestrum doesn't have blood supply so antibiotics won't reach the area
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