Bone And Muscle Flashcards
What are the two different types of bone formation?
Endochondral (long bones, require growth plates)
Intramembranous (flat bones, no growth plate)
What are the steps of intramembranous ossification?
- Ossification center begins in fibrous connective tissue membrane
- Osteoid is secreted into fibrous membrane- entrapped osteoblasts become osteocytes
- Formation of woven bone and periosteum
- Formation of final layer of compact bone
What does growth plate function require?
Amgiogenesis
How do you classify a fracture?
“OLD ACID”
Open vs closed
Location
Degree (complete vs incomplete)
Articular extension
Comminution/pattern
Intrinsic bone quality
Displacement, angulation, rotation
What are the steps of fracture healing?
- Hematoma
- Fibrocartilagenous callus
- Bony callus
- Remodeling
What are salter fractures?
Fractures through a growth plate
Can induce growth deformities
Classified by the fracture location
What are the different types of salter fractures?
1- fracture straight through growth plate
2- fracture through and above growth plate
3- fracture through and below growth plate
4- fracture above and below growth plate
5- growth plate crushed
What are the different types of bone dysphasia?
Craniomandibular osteopathy Osteogenesis imperfecta Osteopetrosis Chondrodysplasia Osteoporosis
What is craniomandibular osteopathy?
"Lion jaw" Bony proliferation of mandible Primarily seen in westies and scotties Autosomal recessive 3-7 moths, stops at 11-13 months Causes pain, difficulty eating/drinking
What is osteogenesis imperfecta?
Defect in matrix synthesis (type 1 collagen)
Characterized by excessive bone fragility, pathologic fractures
What is osteopetrosis?
Failure of bone remodeling
Results in increased bone density
What is chondrodysplasia?
Not just one syndrome
Achondroplasia , disproportionate dwarfism
Osteoporosis?
Bone loss (restoration > formation)
Disuse, malnutrition, corticosteroids
Susceptible to fracture
What is osteopenia?
Decreased number of trabeculae
What are 3 metabolic bone diseases?
Scurvy
Fibrous osteodystrophy
Rickets
What is scurvy?
Only in species lacking L-gluconolactone oxidase (guinea pigs)
Lack of vitamin C->
Decreased lysine and proline hydroxylation in collagen ->
Impaired collagen synthesis ->
Weakened vessel walls and physeal cartilage deformity ->
Periarticular hemorrhage and osteochodrodysplasia
What causes fibrous osteodystrophy?
Primary hyperparathyroidism
Secondary hyperparathyroidism
What is primary hyperparathyroidism?
Functional parathyroid adenomas
Or
Parathyroid hyperplasia
What causes secondary hyperparathyroidism?
Ca:P imbalance in feed
Kidney disease
(Rubber jaw)
What is rickets?
Defect in endochondral ossification in young animals caused by deficiency of vitamin D or phosphorous
What is hypertrophic osteoPATHY
Has pathology!
Periosteum proliferation
Due to intrathoracic mass
Joints NOT involved
What is hypertrophic osteoDYSTROPHY?
Bone disease of young dogs characterized by
“Double physeal line”
Acute inflammation in the primary spongiosa
Necrosis of osteoblasts
Dogs will be lame
What is eosinophilic panosteitis?
Patchy radiodensity in medullary cavity, especially around nutrient foramen
Presents as shifting leg lameness
What is Legg-Perthes disease?
Avascular necrosis of femoral head
Small breed dogs (especially toy poodles)
Occurs prior to physeal closure (4-11 months)
What are some possible causes of osteomyelitis?
Surgery
Penetrating wound
Fractures
Hematogenous spread
Strophic rhinitis is associated with what bacteria?
Bordetella bronchiseptica and pasteurella multocida
What is osteochondromatosis?
Benign growth at growth palate that grows with skeleton
Uncommon
Seen in younger cats
What are diseases of the syovium?
Hypertrophy
Pannus
What is pannus?
Granulation tissue on articular surface that can damage underlying cartilage and progress to ankylosis
What is fibrillation of cartilage?
Formation of vertical clefts in cartilage
Dull, yellow-brown color
What is eburnation?
Polishing of exposed subchondral bone
What are the two types or arthritis?
Osteoarthritis
Inflammatory arthritis
What causes inflammatory arthritis?
Acute infections (penetrating wounds, septicemia) Chronic infections (immune-mediated, viruses, untreated acute arthritis
Arthritis in a goat is probably caused by
Caprine arthritis encephalitis
What causes osteoarthritis?
Decreased proteoglycan synthesis
Increased metalloenzyme synthesis (degrades proteoglycans)
What is osteochondritis dessicans?
Osteochondrosis where a cartilaginous flap breaks off and goes into joint
If an aggressive lesion crosses joint, it is probably
Synovial cell sarcoma
What is intervertebral disc disease?
Annulus fibrosis cracks, tears, or ruptures releasing nucleus purposes
Types:
1- sudden
2- gradual
What is dural ossification?
“Ossifying pachymeningitis” - bone in dura
Generally incidental
What is hip dysplasia?
Typically a disease of large breed dogs (“bunny hopping”
Degenerative, noninflammatory deformation of joints causing subluxation of femoral heads
What is elbow dysplasia?
Disease of large breed dogs (especially german shepherds)
Degenerative, non-inflammatory
Ununited anconeal process
Fragmented medial coronoid process
What are characteristics of normal skeletal muscle?
Myofibers
Peripheral nuclei
Striations
High blood supply
What are the types of muscle fibers?
Type 1- slow twitch, large numbers of mitochondria, postural and sustained activity
Type 2- fast twitch, fewer mitochondria, rapid activity
How are muscle injuries classified?
Distribution= focal or multifocal
Timeline- monophasic or polyphasic
How does muscle respond to injury?
Hypertrophy Atrophy Degeneration Necrosis (+/- calcification) Regeneration Fibrosis
What is muscle degeneration caused by, what does it look like, and what are examples?
Caused by decreased blood flow
Muscle looks pale
Downer cow, post-anesthetic myopathy in horses
What are types and examples of myositis?
Bacterial - clostridium, abscesses
Parasitic - toxoplasma, trichinella, sarcosystis
Autoimmiune- lupus, polymyositis, purpura hemorrhagica
If muscle looks black with gas pockets, what would you suspect?
Clostridium
If muscle has white streaks, what would you suspect?
Sarcocystis
What is masticatory muscle myositis (MMM)?
Unilateral atrophy of masticatory muscle
What are some congenital myopathies?
Malignant hyperthermia Muscular dystrophy Equine rhabdomyolysis Hyperkalemic periodic paralysis Fainting goat syndrome Splayleg
What are some nutritional myopathies?
Malnutrition- atrophy
Vitamin E/selenium deficiency - white muscle disease
Mines in toxicity is most commonly seen in what species?
Horses
What are neoplasias of skeletal muscle?
Rhabodomyoma
Rhabdomyosarcoma
