Longbones

Question 1

What are the two views we want for taking xrays of long bones

Answer 1

Mediolateral + Craniocaudal/Caudocranial

Question 2

What is a mach line?

Answer 2

The apparent line of contrasting density bordering a soft tissue shadow on a radiograph

Question 3

Lysis

Answer 3

Bone loss

Question 4

How soon after disease/Injury can lysis be seen on radiographs?

Answer 4

ca 7-10 days

Question 5

Sclerosis

Answer 5

Increased bone capacity, increased density - hardening of tissue
- sort of like new bone production

Question 6

What specific structures can we see on pediatric patient bones?

Answer 6

Growth plates (epiphyseal lines)

Question 7

Is cartilage visible on radiographs?

Answer 7

No

Question 8

By what age are all growth plates usually closed?

Answer 8

By 18 months in dogs

In cats can be open until age of 2-3 years

Question 9

Physeal scar

Answer 9

Thin horizontal radioopaque line in place of closed physis

Question 10

What are some changes we can see in distal ulna with premature closure of growth plate?

Answer 10

Humeroulnar joint space is widened
Ulna shorter than radius
Craniomedial bowing of radius
Proximal displacement of ulnar styloid process

Question 11

What are some changes we can see in distal radius with premature closure of growth plates?

Answer 11

Increased radiohumeral joint space
Radius shorter than ulna
Increased radiocarpal joint space
Subluxation of proximal ulna

Question 12

Cut-back zone

Answer 12

Area of irregular and hazy bone margins where the metaphysis remodels to the narrower diaphysis during bone growth

Normal in young, rapidly growing bones without the presence of soft tissue swelling

Question 13

Retained endochondral cartilage cores

Answer 13

Cause angular limb deformities.

Retained endochondral cartilage cores have a typical radiographic appearance of a well-defined, flame/triangular-shaped, radiolucent region, with sclerotic rim in the metaphysis, most commonly the distal ulna

Question 14

Nutrient foramen

Answer 14

Small tunnel through the cortex of a long bone containing a nutrient artery that supplies the bone.

Known to mimic oblique fractures on plain radiographs

Question 15

What are often confused with fractures in radiographs?

Answer 15

Physes
Nutrient foramina
Mach lines
Soft tissue shadows (skinfold)

Question 16

Inflammation of bone

Answer 16

Osteomyelitis

Question 17

What reactions give away presence of neoplasia around / in bone?

Answer 17

Lysis and/or new bone formation
(usually combined)
Periosteal reaction

Question 18

Types of periosteal reactions from less malignant to more malignant

Answer 18

1. Solid
2. Onion-peel
3. Sunburst
4. Codman’s triangle

Question 19

Which are more rare in bone, benign or malignant neoplasias?

Answer 19

Benign

Question 20

What kind of appearance do metastatic bone tumors often have?

Answer 20

“moth eaten” appearance

Question 21

What areas are most commonly affected with metastatic bone tumors?

Answer 21

Epiphysis most often
Nutrient foramen, vessel canal area
Humerus, femur

Question 22

Kissing lesion

Answer 22

Is a change in the bone surface where the interosseous ligament connects the radius and ulna, sometimes found near the nutrient foramen

At junction of proximal and middle thirds of caudal radial diaphysis

Mild periosteal reaction

Question 23

Panosteitis

Answer 23

Found in animals up to 7 yo
Looks like patchy areas of increased opacity (“clouds”)
- Periosteal reaction
- Endosteal thickening

Painful inflammation of the outer surface or shaft of one or more long bones of the legs

Question 24

Growth arrest lines

Answer 24

Lines of increased bone density that represent the position of the growth plate at the time of insult to the organism and formed on long bones due to growth arrest.

• Clinically insignificant
• White horizontal lines

Question 25

Osteopetrosis

Answer 25

Rare disorders that cause bones to grow abnormally and become overly dense.

• “Stone bone”

Question 26

Osteopenia and types

Answer 26

Loss of bone density
Radiographically visible when 30-60% of mineral content is lost

Osteomalacia
- Decreased mineralisation
- Normal bone matrix

Osteoporosis
- Decreased mineralisation
- Decreased bone matrix

Question 27

Bone cyst

Answer 27

Seen in puppies or young adults
Around diaphysis or metaphysis of radius (or ulna more commonly)
- Fluid-filled areas inside growing bone that have not developed into osseous tissue or actual bone