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74 Cards in this Set
- Front
- Back
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intramembranous
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starts as fibrous tissue. osteoblasts in the periosteum secrete osteoid. bone grows circumferentially
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endochondral
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starts as cartilage - influx of vessels, osteoblasts, osteoclasts - mineralization of osteoid
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Unique physes
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- wings of ilium do not fuse completely in some dogs
- radial physis - normal undulating shape - ulnar physis - conical shape |
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technique for skeletal rads
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high contrast (low kVp, high mAs)
slow film-screen combo, more detail motion is usually a problem intensifying screen position over area of concern * always do orthogonal view! |
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land marks of cervical spine
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C1 - wings
C2 - dens, spinous processes C6 - transverse processes disk spaces get larger caudally |
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land marks in thoracic spine
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intercapital lgaments
T11 - anticlinal vertebra (no slope) T10-11 disk space is always narrow |
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Approach to spinal rads
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A - alignment
S - soft tissues P - processes I - internal; size, margin, opacity N - nerves/spinal cord; intervertebral foramina E - external margins - shape, size, margin and opacity of vertebral bodies and disc spaces |
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why do imaging?
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"the big D's"
- Detection - Description - Differentials - Diagnosis |
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cutting cone
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subunit of bone responsible for resorptino and formation of mature lamellar bone
makes new osteons |
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normal blood supply to bone
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- nutrient artery through nutrient foramen
- entheses (muscle attachment) - periosteum (minor in normal state) |
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how does blood leave bone?
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entheses
- damage to entheses can significantly affect circulation to bone - congestion causes inc in intramedullary pressure - very painful! |
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approach to appendicular skeleton interpretation
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A - alignment
B - bone (periosteum, cortex, medullary cavity) C - cartilage/joints (ligaments, spaces, periarticular margins) S - soft tissue (intra vs extracapsulare enlargement, gas or mineralization) |
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causes of extracapsular soft tissue enlargement
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edema
hemorrhage inflammation tumor |
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cuases of soft tissue mineralization
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dystrophic mineralization
metastatic mineralization neoplastic mineralization |
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causes of gas in the soft tissues?
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septic process
open wound (big dog-little dog syndrome) recent surgery |
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bone response to infection or trauma
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"ARF"
A - activation R - resorption F - formation Juvenile bone reacts in 5-7 days Adult bone reacts in 7-10 days |
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endosteal proliferation of bone
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sclerosis
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classification of periosteal reactions
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- active/aggressive - indistinct margins (spiculated, amorphous, etc)
- inactive/non-aggressive - well-defined margins, smooth older lesions are smoother and more opaque |
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causes of generalized bone loss
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meatbolic disease
nutritional disease disuse |
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how much bone loss is required to notice radiographic changes
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30-60%
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causes of localized bone lysis
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trauma
infection tumor |
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parts of the joint to evaluate
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ligamentous and capsular attachments
joint space periarticular margins |
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characteristics of a non-aggressive lesion
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- found anywhere
- solid, smooth periosteal reaction - geographic bone lysis (>10 mm area, well defined margins; usually medullary - may displace cortex, but does not destroy it) - short and distinct zone of transition - changes slowly over time |
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causes of non-aggressive bone lesions
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bone cyst - cause unknown
benign tumor cartilaginous exostoses |
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characteristics of an aggressive lesion
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- located in meatphysis (sometimes diaphysis)
- periosteal reaction - rough/spiculated (lamellar, sunburst, amorphous), codman's triangle - moth eaten or permeative lysis - cortical destruction - changes rapidly - long, indistinct zone of transition |
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causes of aggressive bone lesions
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Primary neoplasia
Metastatic neoplasia Fungal infection Bacterial infection Protazoal infection |
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fracture classification
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L - location
E - external communication (open or closed) G - general direction (transverse, oblique) E - extent of damage (complete or incomplete?) N - number (simple or comminuted) D - displacement (of the distal piece) |
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how can you tell that a fracture is open (on a radiograph)?
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look at the soft tissues
- gas adjacent to the fracture segments |
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A single fracture appears to have several different fracture lines going in different directions. What direction is this fracture?
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Spiral
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complications of salter harris fractures
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bone foreshortening
angular limb deformities |
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Classify this fracture
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distal diaphysis of the right humerus
closed oblique complete comminuted (see more than one piece) cranial (can't see this with one view), lateral, proximal |
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Salter-Harris type?
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Type 1
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Salter-Harris type?
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Type 2
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Salter-Harris type?
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Type 4
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Salter-Harris type?
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Type 5
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Salter-Harris type?
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Type II - crosses the physis and part of metaphysis
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Salter-Harris type?
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Type V - see a step at the back of tibia and don't see the thin line of cartilage due to crushing fracture
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fracture type?
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avulsion fracture
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classify this fracture
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pathologic fracture
- recognize lucent, thin cortices - not much blastic activity going on - no history of trauma |
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causes of pathologic fractures
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- tumors
- infections - metabolic diseases (hyperparathyroidism) |
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fracture type?
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folding fracture
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fracture type?
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pathologic fracture secondary to osteosarcoma
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primary bone healing
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- osteonal remodeling
- nearly perfect apposition and alignment required - must be aseptic - early return to function - takes >6 months to return to original strength - cannot see radiographically |
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Secondary bone healing
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- less than perfect reduction, stability or infection
- cartilage bridge formed first - bony callus formed by endochondral ossification - takes longer to reach functional strength than primary - reaches full strength earlier than primary (6-8 weeks) |
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approach to evaluating fracture healing
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ABCD's
A - alignment B - bone C - cartilage D - DEVICE S - soft tissue |
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expected radiographic findings for a healing fracture EARLY in healing process
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widening of fracture line
callus formation |
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expected radiographic findings for a healing fracture LATE in healing process
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opaque, mature callus
increased mineral opacity within the fracture line |
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fracture complications
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- abnormal healing (malunion, delayed or non-union, angular limb deformity)
- sequestrum formation - implant failure |
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Lesions associated with hypertrophic osteophaty (HO)
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1. Manifestation of primary disease:
- thoracic lesion (lung tumor, non-neoplastic lung disease) - abdominal lesion (bladder neoplasia) 1. Radiographic findings: - rough periosteal new boen formation - diaphyseal region of the long bones - typically starts distally |
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aggressive or non-aggressive?
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aggressive
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aggressive or non-aggressive?
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aggressive
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aggressive or non-aggressive?
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non-aggressive
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classify the lysis and comment on aggressiveness of lesion
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geographic lysis, least aggressive
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classify the lysis and comment on aggressiveness of lesion
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moth-eaten lysis, aggressive lesion
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classify the lysis and comment on aggressiveness of lesion
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permeative lysis, aggressive
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classify the lysis and comment on aggressiveness of lesion
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cortical destruction, more aggressive than the other forms that don't destroy the cortex
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radiographic signs of joint disease:
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1. increased capsular thickness or effusion
2. perichondral (marginal) osteophytes 3. Enthesophytes 4. Subchondral erosions 5. Mineralized joint bodies 6. Subchondral bone opacity 7. Subchondral bone cysts 8. Joint space narrowing |
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where would you find perichondral osteophytes?
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at the light blue bit - looks like a bald man's head
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what's wrong with these bones?
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perichondral osteophytes (bald man's head)
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what sign of joint disease can you see in this radiograph?
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enthesophyte at attachment of cranial cruciate
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what's the sign of joint disease in this stifle?
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decreased subchondral bone opacity
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what's the sign of joint disease here?
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mineralized joint body
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what kinds of things can cause mineral opacity in a joint space?
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- joint mice
- avulsed fragments of articular or periarticular bone - osetochondral component - synovial osteochondroma |
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what can cause increased subchondral bone opacity in joint disease?
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- osteosclerosis or eburnation
- stress remodeling |
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what's the sign of joint disease in this joint?
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increased subchondral bone opacity (osteosclerosis/eburnation or stress remodeling)
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what's the sign of joint disease in this joint?
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subchondral bone cyst (proliferation of synovium invades subchondral bone)
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what's the sign of joint disease in this joint?
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altered thickness of the joint
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disk spaces that are normally narrow
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C2-C3
C7-T1 T10-T11 |
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ligaments of the cervical spine
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- dorsal alanto-axial ligament
- transverse ligament of the dens - maintain stability and protect spinal cord |
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ligaments of the spine
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1. dorsal longitudinal ligament
- ventral floor of the spinal canal - CVM-I Syndrome 2. Intercapital ligaments - between heads of ribs - help prevent disc herniation in the thoracic spine |
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standard protocol for spinal radiographs
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collimate to include area of interest
center x-ray beam - cervical spine (C3-C4 and C7-T11) - thoracic spine (T6-T7 and T13-L1) - lumbar spine (L3-L4) |
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correct positioning of lateral spinal view
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- transverse processes superimposed
- intervertebral foramen uniform size - rib heads superimposed |
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correct positioning of the ventrodorsal spinal view
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- dorsal spinous process centered over vertebral body
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important regions of the skull to evaluate:
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teeth
mandible nasal cavity sinuses tympanic bullae calvarium |
