1
Q
Normal depends on
A
- species
- breed
- age
2
Q
Spongy bone aka…
A
- trabecular bone
- cancellous bone
3
Q
Osteon
A
- Sits around haversion canal
- Run legthwise along the bone
4
Q
Osteoblasts
A
- line bony trabeculae
- build new bone
5
Q
Osteoclasts
A
- multinucleated cells
- break down bown
6
Q
Osteocytes
A
- sit in lacunae (one osteocyte/lacuna)
7
Q
Formation
Intramembranous ossification
A
- flat bones (skull)
- no growth plates
- fibrous connective tissue - osteoid secreted into membrane - entrapped osteoblasts become osteocytes - form woven bone and periosteum - final layer of compact bone
8
Q
Formation
endochondral ossification
A
- Long bones
- require growth plates
- predominantly inc in length
- hyaline cartilage model - primary ossification center (periosteum surrounding) - secondary ossification center at end - physeal plate - articular cartilage
9
Q
Growth plate function requires
A
- Angiogenesis
- needs adequately mineralized colagen/cartilage
- needs adequate blood vessel quality
10
Q
Diseases and effect on bone growth
A
- Achondroplasia: effects early stages of cartilage
- Rickets: effects later stages of cartilage and zone of calcification
- Osteogenesis Imperfecta: failure to properly ossify
- Osteopetrosis: failure to remodel
11
Q
Greenstick fracture
A
- incomplete fracture in young animals
- better prognosis
12
Q
Comminution
A
multiple fragments
13
Q
displacement
A
how has distal part moved compared to proximal
14
Q
OLD ACID
A
O: open vs closed
L: location
D: degree (complete vs incomplete)
A: articular extension
C: comminution / pattern
I: intrinsic bone quality (pathologic fracture)
D: Displacement, Angulation, Rotation
15
Q
Fractures: Healing
A
- Hematoma
- Fibrocartilagenous callus
- Bony Callus
- Remodeling
16
Q
Salter Fracture
A
- fractures through a growth plate
- can induce growth deformities
- classified by fracture location
17
Q
Saltr types
A
- Type 1 : straight
- Type 2: Above
- Type 3: Lower
- Type 4: Through
- Type 5: Crush (worst prognosis)
18
Q
Other diseases
A
- dysplasias
- metabolic bone dz
- mescellaneous
19
Q
Dysplasias
A
- Craniomandibular osteopathy (and similar)
- primarily Westies and Scotties
- Autosomal recessive
- 3-7 mo stops at 11-13 mo
- Osteogenesis imperfecta
- defect in matrix synthesis (ie: type 1 collagen)
- characterized by excessive bone fragility: fractures
- Osteopetrosis
- failure of bone remodeling
- inc bone density
- Chondrodysplasia
- not just one syndrome
- Achondroplasia
- disproportionate dwarfism (snorter calf)
- Osteoporosis
- bone loss = resportion > formation
- Disuse, malnutrition, corticosteroids
- susceptible to fx
20
Q
Osteopenia
A
Less trabeculae
before osteoperosis
21
Q
Metabolic bone diseases
Scurvey
A
- only exists in species lacking L-gulonolactone oxidase
- guinea pigs
- peeps (humans)
- Path
- lack vitamin C - dec lysine and proline hydroxylation in collagen - impaired collagen synthesis - weakened vessel walls and physeal cartilage deformity - periarticular hemorrhage and osteochondrodysplasia
22
Q
Metabolic bone diseases
Fibrous osteodystrophy
A
- Primary hyperparathyroidism
- functional parathyroid adenomas
- parathyroid hyperplasia
- Secondary hyperparathyroidism
- Ca:P imbalance in feed
- kidney dz
*big head/bran head in horses
*rubber jaw in dogs
*fibrous connective tissue deposition to stabilize bones that lack Ca
23
Q
Metabolic bone diseases
Rickets
A
- Defect in endochondral ossification
- only in young animals
- deficiency of vitamin D or phospohrus
*rikettic rosary: widening of costo-condral junction along ribs forming beads
24
Q
Hypertrophic osteopathy
A
- Periosteal proliferation
- due to intrathoracic mass (sometimes intraabdominal)
- joints not involved
- etiology unclear
- cutting vagal nerve, makes it go away…..
*big, thick bones on palpation
25
Hypertrophic osteo**dystrophy**
* (metaphyseal osteopathy)
* 'double physeal line'
* young dogs
* acute inflammation in primary spongiosa
* necrosis of osteoblasts
\*better prognosis than hypertrophic osteopathy
26
Eosinophilic panosteitis
* modeling of medullary cavity
* patchy increased radiodensity of legs
* presentation
* shifting leg lameness
* spontaneously resolves on own
27
Legg-Perthes Disease
* Avascular necrosis of femoral head
* small-breed dogs
* occurs prior to physeal closure 4-11 months
28
Osteomyelitis
* **serious**
* Number of possible causes
* surgery
* penetrating wound
* fractures
* hematogenous spread
* dental dz (chihuahua)
* treatment difficult
* hard to get antibiotics into bone (low blood supply)
* can be acute or chronic
\*lumpy jaw in cattle
\*pig turbinate destroyed
29
common place for sepsis lesions in young animals
physis
-hairpin turn of vessels there
\*foals and cows
30
Neoplasia
Osteoma
* benign bone tumor
* rare
31
Neoplasia
Osteosarcoma
* pathologic fracture common
* away from the elbow, towards the knee
* proximal humerus, distal radius
* distal femur, proximal tibia
* doesn't cross joings
\*different than osteosarc in peeps
32
multilobular tumor of bone
* disease of flatbones
* alternating of cartilage and bones
\*difficult to remove
33
Chondrosarcoma
* soft tissue opacity on rads
* difficult to see/dx
34
Osteochondromatosis
* benign masses
* proliferation of growth plate cartilage
* grow with skeleton
* unsightly
35
Multiple myeloma
* neoplasms of plasma cell
* produce bents jones protein in urine
* multi-focal invasion of bone
36
Lymphosarcoma on cytology
* high nuclear to cytoplasmic ratio
* little blue cytoplasm
* mitotic figures
* HUGE lymphocytes
2nd path test
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