Bone - normal, traumatic, inflam

Question 1

cellular components of bone

Answer 1

osteoblasts - make bone
inactive osteoblasts - BBB, control ion movement
osteocytes - most numerous
osteoclasts - resorb bone

Question 2

organic components of bone

Answer 2

90% type I collagen
10% other proteins

Question 3

inorganic components of bone

Answer 3

calcification of osteoid
hyroxyapatite
Ca, P, vitamin D

Question 4

intramembranous ossification
what bones?
key for what?
steps?

Answer 4

flat bones - cranial/facial bones
key for all bones to undergo appositional growth (increase diameter/width)
1. ossification center
2. calcification
3. trabeculae
4. periosteum

Question 5

endochondral ossification
what bones?
steps?

Answer 5

axial and appendicular skeleton
1. cartilaginous skeletal model
2. diaphysis hypertrophies/mineralizes
3. primary ossification centers (diaphysis)
4. secondary ossification centers (epiphyses)

Question 6

describe growth plate growth

Answer 6

longitudinal (interstitial)
orderly zones leading to mineralized matrix for osteoid deposition
closes with skeletal maturation

Question 7

what is wolff’s law

Answer 7

bone deposition inside of curvature
bone resorption outside of curvature
straight bone can withstand more impact

Question 8

difference between valgus and vargus

Answer 8

valgus - lateral deviation of distal limb, common in dogs/horses

vargus - medial deviation of distal limb, rare, occurs in puppies with radial physis damage

Question 9

what is the most common pathology in a puppy with valgus?

Answer 9

premature closure of distal ulna physis

Question 10

steps of fracture repair

Answer 10

1. hematoma
2. fibrocartilage callus
3. bony callus
4. bone remodeling

Question 11

what types of fractures are close opposition of bone segments that enable quick repair back to original strength

Answer 11

closed
oblique
impacted

Question 12

complications of displaced, transverse, spiral fractures

Answer 12

require large callus, decreased healing

continual movement of joints - pseudoarthritis

Question 13

complications of a comminuted fracture

Answer 13

large necrotic bone fragments - bone sequestrum

Question 14

complications of an open (compounded) fracture

Answer 14

bacterial osteomyelitis

Question 15

common routes of osteomyelitis

Answer 15

trauma
local extension
hematogenous (most common cause)

Question 16

what is the most common bacterial isolate from hematogenous osteomyelitis

Answer 16

staphylococcus

Question 17

sequelae of osteomyelitis

Answer 17

bone abscess
sequestrum
involucrum

Question 18

give an example of osteomyelitis from local extension

Answer 18

Actinomyces bovis (lumpy jaw)

Question 19

fungal osteomyelitis

Answer 19

coccidioides
blastomyces
cryptococcus

Question 20

2 causes of non-infectious osteomyelitis

Answer 20

panosteitis
metaphyseal osteopathy - hypertrophic osteodystrophy

Question 21

what disease?
5-12 mo large breed male dogs
shifting leg lameness, forelimb
self-limiting, excellent prognosis
long bone increased medullary density in diaphysis

Answer 21

panosteitis

Question 22

what disease?
large, giant breed dogs (weimaraner, dane)
lameness, swollen distal radius, ulna, tibia
can be self-limiting, recurrent or euthanasia in severe cases

Answer 22

metaphyseal osteopathy - HOD

Question 23

histologic findings of HOD

Answer 23

primary spongiosa
no osteoblasts/osteoid
neutrophils and necrotic debris