Musculoskeletal Dysfunction

Question 1

What are the 5 different systems?

Answer 1

skeletal
muscular
tendon/ ligament
joints
fascia

Question 2

What is a fracture?

Answer 2

traumatic- eg; hit by a car or jump

pathological- weakness over time leads to fracture

Question 3

What are the two fracture types?

Answer 3

corticol- break all the way through

greensticks- breaks halfway through

Question 4

What types of fracture occur?

Answer 4

Chip
Slab
Compound 
Hairline fracture
Stress fracture
Depression fracture

Question 5

What is remodelling?

Answer 5

• not necessarily dysfunctional
• usually occurs due to injury or in response to forces
  ; Wolff’s Law: response of bone to stimuli
• Commonly found in the metacarpals and metatarsals of race horses but occurs across disciplines and across species

Question 6

What is osteopaenia?

Answer 6

generalised demineralisation, disuse

Question 7

What is osteoitis?

Answer 7

inflammation of the bone

Question 8

What is osteoporosis?

Answer 8

degeneration- not yet proved in animals but no studies yet performed

Question 9

What species are bone tumours and cysts more common in?

Answer 9

dogs

Question 10

What is hypertrophy and atrophy?

Answer 10

changes in muscle volume due to increase or decrease in size of individual muscle cells

potentially reversible

caused by

Question 11

What are the three types of Atrophy?

Answer 11

Generalised

• Poor nutrition/malnutrition
• Severe systemic illness – nutritional resource
• Usually occurs symmetrically

Localised

• Paralysis
• Immobilisation (disuse)
• Rhabdomyolysis (rapid breakdown of muscle tissue

Neurogenic

• Localised (PNS)
• CNS damage
• CNS infection

Question 12

What is trauma?

Answer 12

wounds
strain
tear

Question 13

What are wounds?

Answer 13

lacerations
burns
puncture wounds
abrasions

Question 14

What is stain?

Answer 14

commonly used when less fibres are involved and the trauma is localised

Question 15

What is tear?

Answer 15

visible tearing of muscle

eg; muscle bellies or attachments

Question 16

How does the body heal after trauma?

Answer 16

Compartmental Myopathy

Lameness occurring following inflammation and restricted swelling

Common in caudolateral antibrachial

Surgical intervention - Fasciotomy

Fibrosis

Scar tissue mineralises

Forms hard portions of muscle that have no stretch ability

Common on the hind limbs of both dogs and horses

• Turning
• Sliding stops
• Trapped limbs
• Abscess at injection sites

Question 17

What is fibrotic myopathy?

Answer 17

Mainly semitendinosus, occasionally semimembranosis or gracilis

Abnormal gait

Most obvious at walk

Palpable thickening on caudal upper hind limb

Often associated dimple in muscle belly

Also traumatic/degenerative neuropathy

Question 18

What is rhabdomyolysis?

Answer 18

Tyeing up

Condition of enzymic reaction causing breakdown of muscle tissues

Symptoms range from mild stiffness to full muscle cramps affecting regions of the whole body
-Myoglobinuria can be secondary

Often starts 15-30 minutes into an exercise session

Sporadic or recurring

Serum enzyme levels increase

• Aspartate animotransferase (AST) – slower
• Creatine Kinase – quicker

Affects both horses and dogs, mostly effects athletic and competition animals

Question 19

What is polysaccharide storage myopathy? PSSM

Answer 19

Horses only

Accumulation of glycogen and abnormal polysaccharide

• Altered intracellular glucose homeostasis
• Insufficient ATP production
• Rhabdomyolysis

more common in draft breeds

Histopathology
Abnormal accumulation of amylase resistant PAS positive polysaccharide inclusions (often not apparent until > 15months old)

Question 20

What are the clinical signs of PSSM?

Answer 20

stiffness
lethargy
exercise intolerance
muscle contractions

Question 21

What does PSSM cause?

Answer 21

Generalised reduced muscle mass
Muscle atrophy
HL weakness
Reluctance to back

Question 22

How is PSSM prevented?

Answer 22

Prevention
Daily regular exercise
Free exercise in pasture
High fat (13%) low starch (<10%) content of daily digestible energy

Question 23

What is atypical myopathy?

Answer 23

Horses only

Frequently fatal (75-90% mortality)

Rapid treatment essential

Seasonal – grazing horses

Sycamore tree seeds
-Hypoglycin – A

Rapid onset non-exertional rhabdomyolysis