rad Musculo Flashcards
Explain how you would perform screening radiographs for unlocalised lameness ?
Screening when lameness hasn’t been localised
Radiograph each joint (centre the beam on the joint).
- increase the collimation to include >1/2 of the long bones so there will be overlap between radiographs.
6 radiographs per limb
- 3 lateral views and 3 CC views.
List the key points for screening radiographs ?
The key points to remember about screening radiographs
Joint radiographs * collimated out to include the long bones
- this is because most lameness is joint related
- be care full with interpretation (most old dogs will have some joint pathology eg osteoarthritis (OA)
- this is not nessarily the cause of lameness
- Don’t do one joint at a time and stop when you see a radiographic abnormality.
Identify the appropriate textbook to refer to for a given question about a radiographic study ?
Describe how you would undertake a lameness examination ?
How to identify lameness in your patient
- evaluate gait
- palpate joints and limbs
- flex the joints and feel for a restriction of movement
- localise the lameness if possible
If able to localise lameness (20% of general practitioners, 99% of specialist surgeon cases)
radiograph this area + the same area in the other limb
Unlocalised lameness
Carry out screening radiographs of the affected limb + the other limb
- high diagnostic yeild eg. young large breed dog, severe lameness / trauma / fracture
Describe how you would take radiographs for a localised lameness ?
Localised lameness
Radiograph the joint or long bone that the lameness is localised to.
- collimate to this area only
- radiograph the other leg / same views and positioning.
Take two views of each area + do the other leg for comparison.
Joint - include 1/3 of the bone above and below
Long bone - include the joint above and below.
Compare radiographs taken for localised lameness vrs unlocalised lameness ?
Comparing localised and unlocalised lameness.
Localised lameness
Radiograph localised joint / long bone in both legs
- 1/3 above and below joint
- long bone + joint
- two radiogrpahs CC and lateral
Unlocalised lameness
- the most important thing is that the joints are perfectly positioned (screening radiographs are no excuse for poorly positioned joint radiographs).
- Centre radiograph on the joint, extend collimation to include as much of both long bones as possible
- should obtain overlap so the entire long bone is included just in parts
- two shots CC and lateral
When screening for joint pathology can we place both limbs on one radiograph ?
Absolutely not
The only exception is the VD view of the pelvis
Disscuss why we should always radiograph the non pathologoical limb ?
Why should we always radiograph the other limb
- This is the best resource for normal anatomy (especially for this individual animal, unless there is bilateral pathology).
- Localisation of lameness is often wrong
Remember positioning for each limb must be correct to enable a comparison.
(but never attempt to radiograph both limbs in one shot / except with the pelvis).
Provide a definition for an osteophyte, enthesophyte, periosteal new bone and sclerosis ?
Definitions - types of new bone
Periosteal new bone = new bone formoing on the outside
Sclerosis = new bone on the inside of bone
Joints:
Osteophyte = new bone on the edge of a joint (periarticular), indicates osteoarthritis OA of that joint.
Enthesophyte = new bone at the attachment of a ligament, tendon or joint capsule. It indicates degenerative pathology in that ligament, tendon or joint capsule.
On radiographs, determine if periosteal new bone is from an agressive lesion ?
Periosteal new bone
There are two types
- Continuous (Non - aggressive)
- can draw a continuous line along it. Benign
- trauma, panosteitis, adjacent soft tissue inflammation - Interupted (Agressive lesion)
- can not draw a continuous line around it. Aggressive
- DDX neoplasia, osteomyelitis
Identify this pathology and describe some potential differentials ?
Periosteal new bone
New bone on the outside of bone.
Made by the periosteum which is the fibrous lining on the outside of bones.
Differentials
Benign - panosteitis, inflammation in the soft tissues beside bone
agressive - neoplasia, osteomyelitis
hypertrophic osteopathy, hypertrophic osteodystrophy.
Provide a definition of the following terms; osteopaenia, osteomalacia and osteoporosis ?
Definitions
Bone can only react in two ways = new bone or loss of bone
Osteopaenia = reduction in bone opacity
This can occur through two processes
Osteomalacia - abnormal minerlisation (mal-formed)
Osteoporosis - normal bone but a reduced amount (poor in bone)
Identify this pathology ?
Non continuous periosteal new bone.
Identify this pathology and provide a list of differentials ?
Sclerosis
New bone on the inside of the bone
Differentials;
Stress remodelling
Sequestrum (dead bone)
Panosteitis - most common
Bone infarction
Fracture healing
Identify this pathology ?
Continuous periosteal new bone.
What are the three types of bone lysis ?
The three types of bone lysis
- Geographic
Single, well defined.
Usually benign DDX bone cyst, pressure atrophy, benign dental tumour, bone abscess. - Moth eaten
- Multiple smaller areas of lysis that are less well defined.
Agressive DDX neoplasia, osteomyelitis. - Permeative
Multiple pin point areas of lysis.
Poorly defined and hard to see
Agressive - neoplasia, osteomyelitis
Is this bone lesion aggressive ?
Is this bone lesion aggressive
Bone lesions has
- continuous periosteal new bone growth (non aggressive)
- moth eaten lysis. (aggressive)
As a clinicain we make this assessment off the most aggressive lesion present. So if there is both aggressive and non aggressive new bone, bone lysis, ignore the less aggressive.
What is Codman’s Triangle
Codman’s Triangle
Continuous peristeal new bone on the edge of an aggressive lesion.
- periosteum is lifted
- caused via aggressive lesion
- this is not pathognomic for osteosarcoma
Identify this pathology ?
Cortex lysis
What other lesions could indicate an aggressive bone lesion ?
Indicators of aggressive bone lesions / new bone growth
- Interupted periosteal new bone growth
- Moth eaten lysis
- Permeated lysis
- Cortex lysis
- change over time. / progression within three weeks
- Clinical information, signalment, recent orthopaedic surgery, dog attack
List a differential list for aggressive bone lesions ?
DDX Aggressive bone lesions
Neoplasia
Primary neoplasia = osteosarcoma
secondary neoplasia = metastasis eg carcinoma, haemangiosarcoma
Multicentric neoplasia eg lymphoma
Osteomyelitis
Fungal - uncommon in Australia
Bacterial - only seen with an open fracture and orthopaedic surgery
Aggressive bone lesions are likely to be osteosarcoma and much less likely fungal osteomyelitis.
In what location would you expect to see osteosarcoma ?
Osteosarcoma = Away from elbow, close to stifle - metaphysis (wide portions of long bones)
Away from elbow
- proximal humerus
- distal radius
Close to stifle
- distal femur (proximal femur is slightly less common)
- proximal tibia
- distal tibia
- away from the stifle is not so common.
Identify this pathology and its appearance ?
Osteosarcoma
Appearance
Far from elbow, close to stifle
- aggressive new bone and aggressive lysis
- ranges from mostly new bone to mostly lysis
- location = metaphysis
Does not cross the joint
Describe how you go about diagnosing a case of osteosarcoma ?
Diagnosis Osteosarcoma
(Remember that not every aggressive bone lesion is osteosarcoma)
Thorax radiographs for metastasis “met check”
FNA the bone with ultrasound guidance (diagnostic sample 90% of the time)
Bone biopsy (centre of lesion)
- pre biopsy radiographs ( 2 views), use skin staples as a guid
- post biopsy radiograph (2 views), to confirm correct biopsy location.
Identify this pathology and its DDX ?
Metastatic neoplasia - primary neoplasia
- Diaphysis (often)
- older animals
- monostotic or polystotic aggressive lesion
This is potentially a primary neoplasia
Carcinoma
Melanoma
Haemangiosarcoma
spread from mammary gland, prostate, thyroid etc
Identify this pathology and its possible DDX ?
Multicentric neoplasia
- multiple sites
- Lymphoma
Describe what signalment would indicate Osteomyelitis Fungal ?
Osteomyelitis Fungal
Lysis or new bone or both
- any age but usually young
- monostotic or polystotic aggressive lesion
Location = anywhere, axial and perpendicular skeleton.
Under what circumstances would you suspect Osteomyelitis bacterial ?
Osteomyelitis bacterial
Never seen in adult cats and dogs; rare in pups and kittens
- common in foals and calves
- often polystotic
Suspect when
- there is an open fracture
- following orthopaedic surgery
What is the Epiphysis, Metaphysis and Diaphysis of a long bone ?
Bone anatomy
E = Epiphysis
M = Metaphysis
D = Diaphysis
Describe the signalment and clinical signs of patients with Panosteitis ?
Panosteitis
Clinical signs
- Acute onset lameness in one or more limbs (no trauma)
- each episode - 2 weeks (can go on for upto 9months).
- pain on palpation of long bones
Signalment
- Relatively common in large breed dogs; especially German GSD
- usually young 8-18 months; but has been reported from 2months to 7 yearss
Identify this pathology of the long bone and describe the radiographic signs ?
Panosteitis
Radiographic signs
- Sclerosis (new bone on the inside)
- always compare to the other limb
- +/- Periosteal new bone (continuous)
Sclerosis is the most common finding, often small areas. Always compare to the other limb.
How would you describe the appearance of a fracture on radiograph ?
Description of a long bone fracture (6)
- Complete or incomplete
- Open or Closed
- Where - diaphysis, metaphysis, epiphysis or articular
- Types - transverse, oblique, spiral
- Simple or Comminuted (> one fracture line)
- Displacement
The rule of displacement is to describe the displacement of the distal fracture segment relative to the proximal segment eg
cranial displacement of the tibia.
At what point in time is a green stick fracture most visible ?
Greenstick fracture.
A greenstick fracture is an incomplete fracture.
Fractures are most visible 7-10 days after trauma due to resorption of the fracture margins.
So if a fracture is not seen immediately after trauma repeat radiographs after 7-10 days.
What is a Salter- Harris fracture ?
A Salter Harris fracture is a fracture of the open physis.
Therefore this can only occur in young dogs and cats while the physis remains open.
Describe a Salter Harris fracture Type 1 to 5 ?
Salter Harris fracture - fracture of the open physis.
Type 1 - straight through
Type two - straight up
Type 3 - Straight down
Type 4 - Straight through top and bottom
Type 5 - Compaction
Only young dogs and cats can get a Salter Harris fracture as the physis has to be open
Identify and describe this pathology ?
Salter-Harris type one
A straight fracture through the physis.
Discuss pathological fractures and list the causes ?
Pathological fractures
These occur due to underlying pathology in the bone
(Suspect from history - no history of trauma)
Pathological fractures DDX
- Agressive bone lesion eg neoplasia, osteomyelitis
- incomplete ossification of the humeral condyle
- secondary nutritional hyperparathyroidism
- Orthopaedics (empty screw hole, weak bone at the end of plate).
Describe the two types of angular limb deformity in the thoracic limbs ?
Angular limb deformity - the thoracic limbs.
Normal - breed
- normal in chondrodystrophic breeds eg basset hound
- the legs bow and the carpus rotates outwards
- can still cause lameness
Due to trauma
- trauma to the open physis of the radius or ulna
- affected bone stops growing
Describe the pathology behind angular limb deformity due to trauma ?
Angular limb deformity due to trauma.
Trauma occurs to an open physis of the radius or ulna
- patient still growing < 12months of age so physis closes early
- affected bone stops growing and is shorter
- shorter bone pulls away from the elbow joint (sublaxation).
Most often occurs in the distal ulna
This causes the carpus to rotate outwards / laterally. This is called carpal valgus.
Why is angular limb deformity more often observed in the cat then the dog ?
Angular limb deformity
Dog = V or cup shaped
Cat = linear
Most of the length of the radius and ulna comes from the distal physis
- trauma = early closure
- most frequent distal ulna physis in the dog as it is cup shaped, thus more affected by trauma.
Identify this pathology, and what you observe ?
Angular limb deformity
young animal
carpal vulgas
Radiographic change = short ulna is pulled off the elbow joint so the joint space is wider.
When a patient has trauma to the distal thoracic limb, ensure the owners monitors closely for developing angular limb deformity.
(trauma to physis is often missed upon radiograph, so it can never be completely ruled out).
Describe the pathology of Hyperparathyroidism ?
Pathology Hyperparathyroidism
(metabolic bone disease).
- Caused by high parathyroid hormone which causes a loss of calcium from the bones.
- usually only affects the bones of young patients as they are still growing thus more susceptable.
Renal secondary Hyperthyroidism
- kidney failure due to renal dysplasia
- reduces phosphorus excretion and reduces production of vitamin D
- Parathyroid hormone is released causing a loss of calcium from the bones
Secondary nutritional hyperparathyroidism
- all meat diet pups and kittens
- meat contains a large amount of phosphorus
- poor calcium: phosphorus ratio in diet
- high phosphorus reduces vitamin D production in the kidney
- Release parathyroid hormone causing a loss of calcium from the bones.
What would we observe on radiograph of a patient suffering from secondary renal hyperparathyroidism ?
Secondary renal hyperparathyroidism
Renal dysplasia
- abnormal kidney architecture on ultrasounds
- renal hyperparathyroidism only clinically affects the head
- young animal
- teeth may appear to be floating
Describe what you would observe on radiograph of a patient suffering from secondary nutritional hyperparathyroidism ?
Secondary nutritional hyperparathyroidism
On radiographs
- usually a young animal all meat diet
- pathological fractures due to weakened bones (often incomplete)
- osteopenia
- bones reduced opacity and the cortex is thin
Describe the signalment and clinical signs of Hypertrophic Osteodystrophy ?
Presentation of Osteodystrophy (HOD)
Signalment
- rare
- large breed young dogs (2-7 months)
Clinical signs
- painful swelling over metaphysis
- fever, lethargy, diarrhoea, anorexia
- self limiting usually
There is an unknown aetiology, but potentially systemic infection
Histology
- neutrophilic response
- increased osteoclast numbers.
Identify and describe this pathology ?
Hypertrophic osteodystrophy (HOD)
Distal radius, ulna and tibia are most commonly affected.
- double physeal line ( thin lucent line parallel to physis)
- chronic - periosteal new bone along the metaphysis (may appear aggressive)
Describe the signalment and clinical signs of Hypertrophic osteopathy ?
Hypertrophic osteopathy
Signalment
- older dog with all limbs affected (painful and swollen)
- usually present with clinical signs of lameness before clinical signs of the primary cause.
Identify this pathology ?
Hypertrophic osteopathy
Describe the pathology and radiographic signs of Hypertrophic osteopathy ?
Hypertrophic osteopathy
(older dog, all limbs)
Pathology
Periosteal new bone on all limbs secondary to pathology elsewhere
- usually lung neoplasia so rad thorax
- pregnancy heart worm
- resolves when the primary cause is removed
Radiograph
- periosteal new bone
- usually continuous irregular or palisading
- diaphysis only
- more severe in the distal limb (carpus and tarsus)
Describe the systematic approach to a diagnoses of lameness in a dog ?
Systematic approach to lameness
- Signalment, history and orthopedic exam
- Differential diagnosis list
- Evaluate radiographs for those differentials
- Systematic approach SABCD
Describe any abnormalities using the Roentgen signs.
What dose SABCD stand for ?
SABCD
S = softe tissues
A = alignment (angular limb deformity, fracture, congenital)
B = bone (cortex, medulla)
C = cartilage
D = device (orthopaedic implants)
Describe the normal anatomy of the joint ?
Anatomy
Subchondral bone
Articular cartilage
In practice it is not expected to know the normal appearance and names for all anatomy - but which text book is best for refferal ?
Provide a differential list for joint effusion ?
Joint effusion DDX
- osteoarthritis
- cruciate ligament disease
- osteochondrosis
- immune mediated (polyarthropathy)
- trauma to intraarticular structures
- patella luxation
- neoplasia of the joint
Describe the difference between intracapsular vrs extracapsular joint effusion ?
Intracapsular vrs extracapsular
Intracapsular joint effusion
Intracapsular = softe tissue swelling
- inside the joint capsule (joint effusion)
- eg proliferation of the synovial linning
Extracapsular = soft tissue swelling
- outside the joint capsule
- ie skin, subcutaneous tissue, muscle
- eg cellulitis, oedema in the skin overlying the joint.
Identify which joint we can differentiate between intracapsular and extracapsular joint effusion ?
Differentiation of intra and extra joint effusion
Easiest
- Stifle and tarsus
- as there is a large fat pad
- only on lateral projection
Moderate
- carpus and manus
- due to soft tissue thickness around the joint being so thin, enabling joint effusion to be seen
Can not tell - the rest - shoulder, elbow, hip. This is because there is too much muscle around the joint.
Describe the four possible types of new bone we can see ?
Four types of new bone
Sclerosis
Periosteal new bone
Osteophytes
Enthesophyte
Identify this pathology and what you observe ?
Osteoarthritis
Degenerative disease which worsens over time.
Joint effusion
Periarticular osteophytes
- new bone at the edge of the articular cartilage
Enthesophytes
- new bone at the attachment site of the joint capsule, ligaments or tendons.
Describe the radiographic signs of aggressive joint disease ?
Radiographic signs of aggressive joint disease
Lysis on both sides of the joint
- it may however, initially only be present on one side of the joint (early aggressive joint disease)
- very early on there may only be signs of soft tissue swelling
Identify this pathology and create a differential list ?
Aggressive joint disease
(Why lysis on both sides on the joint).
Differential list
- joint neoplasia of soft tissue such as the synovium
- septic arthritis (haematogenous spread from outside, surgery, wound)
- immune mediated arthritis (bilateral joint effusion)
Describe the signalment and radiographic signs of joint neoplasia ?
Joint neoplasia
Signalment
- older medium to large breed dog
Radiographic signs
- lysis on both sides of the bone
- stifle and elbow
- haemangiosarcoma, synovial cell sarcoma
Describe the signalment and radiographic signs of septic arthritis ?
Septic arthritis - painful infection of the joint
(severe effusion, lysis both sides of the joint)
Signalment
- often > 1 joint
- common in foals and calves (rare in kittens /pups)
- almost never adult dogs
- nidus of infection is distant via umbilicus
Direct inoculation
- trauma, foreign body, iatrogenic
Radiographic signs
- joint effusion
- +/- bone lysis that may be seen on one side or both sides of the joint
Compare the signalment between joint neoplasia, septic arthritis and osteosarcoma ?
Joint neoplasia
- old dog
- elbow and stifle
- lysis on both sides of the bone
- litle new bone growth as periosteum is destroyed on the way to the bone
Septic arthritis
- not cats and dogs unless a complication from surgery
- joint effusion at time of diagnoses, progresses to lysis of bone
- no periosteal new bone growth
Osteosarcoma
- lysis on side of the joint
- peristeal new bone growth is common
- typical locations and signalment (away from elbow, toward stifle)
Define the disease of osteochondrosis and describe its signalment ?
Osteochondrosis
Abnormal joint cartilage in young dog
Signal ment
- medium to large breed dog
- abnormal joint cartilage
Identify this pathology ?
Osteochondrosis of the elbow
Describe how you would observe osteochondrosis on radiograph ?
Radiograph Osteochondrosis
Small focal lucency in very specific locations.
- cartilage not seen on radiogragh
- to be seen must affect the underlying subchondral bone
The exact locations
- head of humerus
- medial aspect of the humeral condyle
- medial or lateral femoral condyle
- medial ridge of the talus
Identify the four locations of osteochondrosis ?
The locations of osetochondrosis
- head of the humerus
- medial aspect of the humerus
- medial or lateral condyle of the femur
- medial ridge of the talus
Define joint mouse ?
Joint mice
Osteochondrosis fragment
fracture fragment in joint
avulsion of ligament
osteophyte
