Lame - Diagnostic imaging - bone Flashcards
What can greatly change radiographic evaluation?
Positioning
Exposure/processing
What are some signs you can see in soft tissue that suggest disease?
Swelling
Muscle wastage
Foreign material
Gas
Effusion
What joint can you tell if there is an effusion of the joint capsule?
Stifle
How can you tell if there is an effusion of the stifle joint capsule?
Radiolucent lines of fat running down the fascial planes on the caudal aspect of the stifle - if these are pushed backwards then it suggests distention of the joint capsule
Also fat in between the patella and the joint capsule - radiolucent unless squashed
What is an example of when alignment can help to diagnose a condition on radiograph?
In cranial cruciate rupture, when the midpoint of the femoral condyle doesnt align with the midpoint of the tibia bumps - cranial draw
What is the outline of the bone called?
The cortex
What can be mistaken for a fracture in the cortex of a bone?
Nutrient foramen - well defined lucency extending through one cortex of the bone into the medulla
This is normal
What can you assess of the cortex to determine if it is normal?
The outline - is it continuous
Thickness of cortex
What is the outside and the inside of the cortex called?
Periosteal surface - outside of bone
Endosteal surface - inside, next to medulla
What can you assess of the medulla on radiograph?
Integrity of trabeculae
Changes in opacity
What is a normal change in opacity of the medulla?
The medulla in the mid-diaphysis of long bones is naturally more radiolucent - blacker, seems more see through
What is a condition that affects long bones and is shown in the medulla on radiograph?
Panosteitis
What is panosteitis?
Self limiting disease in young large breed dogs that affects the long bones causing shifting lameness between one leg and the other
What does panosteitis look like on radiograph?
Uneven opacity with some areas of long bone more radioopaque and some more radiolucent - patchy
What can you assess of articular surfaces on radiograph to determine disease?
Contours of surfaces - is end of bone shaped normally
Subchondral bone - normal opacity, any defects indicating osteochondrosis
Congruity - alignment normal, subluxation present
What are physes?
Growth plates
What can look like fractures in young animals?
Physes - are open in young animals
Can look like fractures, but often arent
They can fracture however - need to know how to differentiate this
What can cause confusion in cases of osteochondrosis?
Condition is bilateral but animal may only be lame on one leg
How can you tell there is bone loss?
Opacity of bone reduces - more like soft tissue
Thinning of cortices - outer bone
Thinning of medullary trabeculae
How much mineral has to be lost to be radiographically apparent?
40%
So will be severe if can see on radiograph
What can cause focal/multifocal bone loss?
Infection - osteomyelitis
Neoplasia
Trauma
What can cause diffuse bone loss?
Disuse
Nutritional/metabolic cause
What is an example of a disease causing nutritional bone loss?
Secondary hyperparathyroidism - calcium phosphorus imbalance leading to mineral resorption from bone
What can cause increased bone production?
Trauma
Neoplasia
Infection - osteomyelitis
Craniomandibular osteopathy
What is smooth pattern of distribution in bone production likely to be caused by?
Benign chronic lesion
What is spiky/spicular pattern of distribution in bone production likely to be caused by?
Active aggressive neoplastic lesion
Infection
What are features of an aggressive lesion causing increased bone production?
Spicular spiky edges - no well defined margins
Long zone of transition - not a discrete edge
Mixed production and destruction of new bone - patchy
When might there be both periosteal and endosteal thickening/bone production?
Callus
How can you tell if it is bone formation compared to dystrophic calcification of surrounding soft tissues?
If there are trabeculation to the bone being produced
If it is attached to the periosteum
What is the appearance of a benign bone lesion?
Well marginated
Short zone of transition
Smooth thinned cortices
Expansile but no cortical destruction
What is craniomandibular osteopathy? What does it occur in?
New bone formation on the cranium, tympanic bullae and mandible
Occurs in young small breed dogs - terriers
What is hypertrophic osteopathy?
New bone production on the periosteum of limb bones in response to a space occupying lesion in the thorax or abdomen
Mechanism is unknown
What is calcinosis circumscripta?
A build up of mineralisation in the soft tissues around pressure points eg. shoulders, hock
How can you differentiate calcinosis circumscripta from bone formation?
Take radiographs in multiple different planes - will see it is not attached to the bones
What features can you look at to help to describe and classify different fractures?
Orientation
Number and position of fragments
Involvement of growth plates
Involvement of articular surfaces
What are some different orientations of fractures?
Transverse - straight across bone
Oblique
Spiral
What is a comminuted fracture?
Divides the bone into multiple fragments
What is a simple fracture?
Divides bone into two pieces
What does it mean if the bone is distracted in a facture?
Fragments moved apart
What does it mean if the bone is impacted in a facture?
Shortened a bone
What does it mean if the bone is overriding in a facture?
The fragments are displaced and overlapping
What is the classification for physial/growth plate fractures?
Salter-Harris classification
What is the convention for describing the position of the fracture?
Describe the distal part of the fracture relative to the proximal part
eg. radius has moved cranially and proximally relative to the humerus
Why is aging a fracture important?
Will be useful if determining if it was a pathological fracture - underlying pathology in the bone
How do you age a fracture?
Look at the margins of the fracture
What does a recent fracture look like when aging fractures?
Recent - margins are well defined
What does the bone look like after 7-10 days when aging fractures?
Rounder, less well defined ends with some bone loss
What happens after 10-14 days in fracture aging?
Periosteal new bone trying to form a callus over fracture site
What happens after 4-6 weeks in fracture aging?
Bony union and then remodelling
What is luxation?
Complete separation of the joint surfaces
What is subluxation?
Displacement of joint surfaces but partial contact still remains
What are two causes of luxations/subluxations?
Traumatic
Congenital
What causes nutritional secondary hyperparathyroidism?
Low calcium or high phosphorus in the diet
What does nutritional secondary hyperparathyroidism cause?
Mineral resorption of bone - generalised decrease in bone opacity
Thinning of the cortices - cause fractures
Normal growth plates
What types of fractures can nutritional secondary hyperparathyroidism cause?
Complete or folding
What is different about nutritional secondary hyperparathyroidism caused by renal failure?
Skull is most affected - rubber jaw
Teeth look like they are floating
Similar radiographic appearance
What causes rickets?
Lack of vitamin D
What are the radiological features of rickets?
Affects the physes - widened physes
Flares metaphyses
Overall mineralisation often normal
What animals tend to get hypervitaminosis A?
Cats fed a diet of mostly liver
What does hypervitaminosis A cause?
Periosteal new bone formation in the cervical spine, spine and limb joints
Can cause fusion of bone
Wont correct after diet corrected
