Special Q1-3

Question 1

Long bones consists of:

Answer 1

Epiphysis
Metaphysis
Diaphysis
Physis (growth plate)
Cortex = periosteum

Question 2

How to take x-rays of the bones?

Answer 2

Use low kV and high mA to avoid overexposure
Use grid for long bones
Keep area of interest parallel to the cassette

Question 3

Normal closing of growth plates are:

Answer 3

Dogs: 12 months
Cat: 18 months
Distal radius and ulna - 6-12 months

Question 4

Causes of premature closing of growth place and diagnosis:

Answer 4

Most common in radius and ulna, causes elbow dysplacia (ED).
* Lack of growth hormone and TSH (thyroid stimulating hormone)
* Injury to physis
* Osteomyelitis before the end of growth period –> shortening of limbs
* Hyperthyroidism/metabolic disorders
Diagnosis: x-rays every 7 days for several weeks to observe changes in growth plate

Question 5

Which bones are most often evaluated for age determination?

Answer 5

Long bones: femur and humerus

Question 6

What is a periosteal reaction?

Answer 6

Formation of new bone in response to injury or other stimuli.
2 groups: continuous and interrupted.
Smooth and intact = benign.
Broken or interrupted = aggressive.

Question 7

Types of periosteal reactions:

Answer 7

Solid/smooth: Along the cortex, slow growth, least aggressive, inflammation.

Lamellated/onion: periosteum cannot produce new bone as fast as the growth of the lesion, metabolic disease.

Sunburst: too rapid growth of lesion. Tiny fibres stretch out from periosteum and ossify. Osteosarcoma.

Codman’s triangle: lesion grow so fast that periosteum cannot even produce a thin shell, but there is bone filling underneath. Primary bone neoplasia.

Palisade: new bone is formed extending in columns outward at right angles from the cortex. Brush-like. Hypertrophic osteopathy and osteomyelitis.

Amorphous: the most aggressive.

Question 8

Characterize bone tumours:

Answer 8

Neoplastic growth of bone tissue - lytic, proliferative or mixed.

Question 9

Primary bone tumours location and types:

Answer 9

Commonly on the distal femur and proximal tibia.

Benign: stay in place, not fatal. Osteoma, osteochondroma, osteoblastoma and giant-cell tumour.
Malignant: cancerous, can spread. Osteosarcoma, condrosarcoma.

Question 10

Characterize secondary bone tumours:

Answer 10

Tumours that are metastatic lesions which have spread from other organs.
Most commonly spread from carcinomas from breast, lung and prostate.

Question 11

Describe hypertrophic osteodystrophy:
Definition, occurrence, associated with and causes.

Answer 11

Failure of normal development or abnormal metabolism in bone.
Fast growing and large dog breeds, first sign between 2-7 months.
Associated with:
- Over-supplementation of vitamins and minerals
- Hypovitaminosis C
- Inflammation
- Canine distemper virus
Cause: decreased blood flow –> failed ossification –> necrosis and inflammation

Usually bilateral, especially radius, ulna and tibia.

Question 12

Radiological signs of hypertrophic osteodystrophy include:

Answer 12

Early: transversely radiolucent zones within the metaphysis that are parallel and adjacent to physis
Diffuse soft tissue swelling
Irregular, new periosteal bone formation around the metaphysis (‘‘collar’’)
Radiolucent zone become opaque in chronic stage

Question 13

Characterize juvenile osteodystrophy:

Answer 13

Nutritional secondary hyperparathyroidism.
Generalized skeletal demineralization (osteoporosis).

Caused by increased parathyroid hormone levels causing resorption of calcium from bones.
Increased resorption of bone by osteoclasts releasing Ca into bloodstream.
Decreased bone opacity.

Question 14

Radiological signs of juvenile osteodystrophy:

Answer 14

Cortical thinning, reduced contrast between bones and tissue, folding fractures.
Corrected with diet.

Question 15

Characterize osteomyelitis:

Answer 15

Bacterial infection of the bone causing inflammation of the bone and marrow.
Malformation of the bone due to growth in certain areas (limb appearance).
Mixed, lytic-proliferative lesion.
Palisade periosteal reaction.

Question 16

Radiological signs of osteomyelitis:

Answer 16

Bone cysts appear as radiolucent bubbles within the bone.
Lysis of bone cause radiolucency (dark).
Loss of normal trabecular pattern within metaphysis.

Question 17

Characterize panosteitis juvenilis:

Answer 17

An inflammatory disease of long bones, characterized by proliferation and remodeling.
In large breeds.
Clinical signs: shifting leg lameness without history of injury or pain on palpation.

Question 18

Radiological signs of panosteitis:

Answer 18

Focal, patchy areas of increased opacity within the medullary cavity.
Outer surface of bone looks roughened.
With progression, a smooth periosteal reaction develops.

Question 19

Characterize osteochondrosis:

Answer 19

Abnormality in endochondral ossification - interruption of blood supply to a bone, especially to the epiphysis.

Cause necrosis of bone that later regrows, causing irregular areas of radiolucency and radiopacity. Articular cartilage becomes thickened, chondrocytes in deeper layers dies, causing failure of ossification of the surrounding cartilaginous matrix.

Question 20

Radiological signs of osteochondrosis:

Answer 20

Defect in subchondral bone which frequency has sclerotic margin.
Loose flap of calcified cartilage may be overlying the cartilage.

Question 21

What are radiological signs of fractures?

Answer 21

Soft tissue swelling
Gas or foreign material within soft tissue
Malalignment of the limb in complete fractures
Discontinuity of the cortex with radiolucent lines
Fragmentation
Callus

Question 22

Classify fractures:

Answer 22

1. Simple - only 2 fragture fragments
2. Compound - break the skin
3. Complex - dislocation of bone
4. Comminuted - multiple fractures
5. Complete - involves entire bone
6. Incomplete - cortex only
7. Avulsion - separation of small piece near joint margin
8. Transverse - straight line through the width of the bone
9. Oblique - through the width of the bone
10. Impacted - due to compression

Question 23

Classify fractures according to Salter-Harris:

Answer 23

Type 1 - simple separation through the physis
Type 2 - Metaphyseal fragment remains attached to epiphysis
Type 3 - Fracture through epiphysis into physis
Type 4 - Fracture through epiphysis and metaphysis
Type 5 - Crush injury to physis
Type 6 - Incomplete fracture with bridging of new periosteal bone over the physis

Question 24

Characterize healing of fractures:

Answer 24

Time depends on age, type of fracture, fixation, soft tissue damage, vascular supply or systemic disease. More rapidly in young than old.
1) Formation of haematoma - gradually absorbed
2) Formation of fibrocartilaginous callus
3) 4-12 weeks: bony callus formation (mineralized)
4) Bone remodelling: bony callus –> compact bone

Question 25

Name complications from bone fractures:

Answer 25

Delayed union: normal healing, but all stages occur later than normal
Malunion: bone fuse with incorrect allignment
Non-union: disruption of blood supply
Excessive callus formation
Osteomyelitis