MSK 1

Question 1

why do we want to use high exposure with MSK rads? how can you accentuate this?

Answer 1

• because bone is high in density we need the high contrast/exposure
• can be accentuated with a low kVP

Question 2

in large animal, where is the marker placed for MSK rads?

Answer 2

lateral or dosal/cranial

Question 3

what does cartilage look like on rads?

Answer 3

trick question: nothing! it shows up as black space because of it’s high water content

Question 4

in regards to terminology, the switch from cranial to dorsal happens at which joint?

Answer 4

the carpus/tarsus

Question 5

why would you take a rotated lateral pelvis view rad?

Answer 5

to differentiat where lesions are; sicne the acetabuli are usually superimposed, if there is pathology there, you want to slightly separate them to see where exactly the problem is

Question 6

if a VD of the pelvis is taen properly, the medial aspect of the femur should line up/cross over with the

Answer 6

ischial tuberosity. the lesser trochanter of the femur shoud line up nicely with it!

Question 7

what is the difference between the trochlear ridges and the chondyles?

Answer 7

the chondyles are the articular surface with the tibia, and the trochlear ridges articulate with the patella but not the tibia

Question 8

if you look at a VD of the pevlis and the obturators look asymmetric, what does this tell you?

Answer 8

it means you need to retake the rad, you were probbaly a little bit oblique

Question 9

how much of the femoral head should normally be “covered” by the acetabulum?

Answer 9

50% or greater

Question 10

the interchondylar eminince of the tibia is where _____ inserts

Answer 10

the cruciates!!!

Question 11

true or false: the absence of luxating patella on rads rules out luxating paella as a differential

Answer 11

false! just because the patella isn’t off midline and visibly luxating doesn’t mean the patient does not have luxating patella!

Question 12

in small animal practice: if your radiographic focus is the bone, say the femur, what are your landmarks for the radiograph (aka how much should you include)

Answer 12

you sould center the image on the bone of interest, and include the joint proximal and distal to the joint

Question 13

if your area of interest for the rad is a joint, what are your landmarks, aka, what should you include in the rad?

Answer 13

should be centered on the joint of interest, and include 1/3 of the adjacent diaphyses on either side of the joint, proximally and distally

Question 14

please remember that romero said bones are twinkies and not oreos. please explain what he meant

Answer 14

on a rad it looks lke there’s just two cortices, when in reality the bone is cylindrical. just remember it’s not an oreo

Question 15

what is an apophysis?

Answer 15

in young animals, a separate area of ossification, usually at sites of insertion for soft tissues

Question 16

what is the periosteum?

Answer 16

the soft tissue covering the cortex of the bone

Question 17

use the red arrows to label the bone from top to bottom

Answer 17

• epiphysis
• physis
• metaphysis
• diaphysis

Question 18

what is the arrow pointing to?

Answer 18

an apophysis, a separate ossification center. this one is the tibial tuberosity

Question 19

label the bone types on this rad from top to bottom

Answer 19

• cortical bone (cortex)
• trabecular bone (medulla)
• subchondral bone (on articular surfaces/joints)

Question 20

what is the top arrow pointing to?

Answer 20

a nutrient foramen

Question 21

what are the ABCD’S of reading the film of an MSK rad?

Answer 21

• alginment
• bone
• cartilage
• device
• soft tissues

Question 22

the most notable fat pad is located in the

Answer 22

stifle

Question 23

should you be able to see cartilage normally on rads?

Answer 23

no! cartilag and joint fluid have similar opacity on radiographs and often will appear invisible because o the high water content

Question 24

why is sedation important for getting rads of fractures?

Answer 24

because motion unsharpness will lead to missed hairline fractures, esp with LA

Question 25

what is the difference between chip fracture and a slab fracture?

Answer 25

a chip fracture is exactly what it sounds like, just a chip off a bone. a sab fracture goes through 2 joints, like when a peice of a glacier melts and falls of the main iceberg

Question 26

if physical exam findings are highly suggestive of a fracture, but rads are not revealing, consider….

Answer 26

recheck rads in 7-10 days to allow some of the healing process to happen, which will make the fracture become more apparent/visible

Question 27

yur fracture will only be visible if the beam is….

Answer 27

parallel to the fracture axsis. think of a big canyon or valley with walls on the side, and you want the beam to go right through the middle to be parallel with the valley/fracture

Question 28

describe the healing physiolgoy fora fracture in each of these time points:
- day 1
- 5-10 days
- 10-20 days
- more than 30 days
- more than 3 months

Answer 28

day 1: sharp margins/good definition of fracture
5-10 days: margins soften (like a melting ice cube), and the fracture gap widens
10-20 days: callus formation, fracture narrows
more than 30 days: fracture dissapears
more than 3 months: continued remodelling, cortical shadow appears.

Question 29

radiographs are sensitive for fractures, but not as sensitive as _____

Answer 29

nuclear scintigraphy

Question 30

what are the advantages and disadvantages of nuclear scintigraphy used to detect a fracture?

Answer 30

• good: it is very sensitive for small fractures and will show colletion in areas of increased bone turnover
• bad: it’s not specific, it can’t tell you what the fracture us or what kind of fracture, etc

Question 31

bone healing depends on what 5 things?

Answer 31

• age (young animals heal faster)
• location (areas with good or bad blood supply)
• fracture type (comminuted vs simple)
• stabilization (remember too much stability also bad)
• concurrent disease

mneumonic: a little fish ate cheese

Question 32

what, according to romero, is the difference between primary and secondary bone healing ?

Answer 32

primary: good reduction of the fracture and good stabilization, little to no periosteal reaction
secondary: there is a bridging callus that happens in 5 stages

Question 33

briefly describe the 5 stages of radiographic bone healing

Answer 33

stage 1: sharp margins, well defined, soft tissue swelling usually present but can be variable
stage 2: 5-10 days post fracture, resoprtion of the fracture margins, loss of sharp magination, widening of fracture gap
stage 3: 10-20 days post fracture, formation of the endostal and periosteal callus, fracture gap decreases
stage 4: more than 30 days post fracture, fracture lines dissapearing and callus remodelling
stage 5: months after fracture, continued remodelling of the callus, cortical shadow, cortical remodelling alone lines of stress

Question 34

what phase of bone healing is this and why?

Answer 34

stage 1-2: there are sharp fracture margins

Question 35

what phase of bone healing is this and why?

Answer 35

stage 3: can see callus formation and the margins of the fracture become less sharp and more hazy

Question 36

what phase of bone healing is this and why?

Answer 36

stage 4: there is remodelling, a thickened callus, and the gap is nearly closed

Question 37

what stage of fracture healing is this and why?

Answer 37

stage 5, can’t see the fracture anymore and the callus has been reduced almost completely

Question 38

what are the 3 big “complications” with fracture healing?

Answer 38

• malunion
• delayed union
• non union

Question 39

what is a bone sequestrum?

Answer 39

a non viable bone fragment, aka dead bone that has lost blood supply and will not heal, often becomes infected

Question 40

in regards to a bone sequestrum, what is an involcrum, and what is a cloaca?

Answer 40

involcrum is the parent bone bed
cloaca is the draining tract

Question 41

true or false: bone sequestrums can’t be sterile

Answer 41

false! it can be sterile. if there is a lack in blood supply, the bone fragment can die and become nonviable without an infection present