Skeletal system

Question 1

Causes of laminitis…?

Answer 1

Caused by: EMS -> insulin resistance/obesity
Equine Cushing’s syndrome
inflammation from grain overload

Question 2

Symptoms of laminitis…?

Answer 2

Swelling of pastern & coronary band
Depressed
Ears flat back
Increased resp, HR, temp
Divergent lamellar growth rings
Widening of white line

Question 3

Structural changes of hoof due to laminitis?

Answer 3

Distal phalanx rotation

Corium necrosis & haemorrhages

Question 4

Other limb conditions?

Answer 4

Bowed tendons (tendonitis) - strain of flexor tendon -> inflammation ->bowed tendons
Most common in racehorses

Question 5

Navicular disease…?

Answer 5

Common cause forelimb lameness (QT & TBs)
Erosion/necrosis of navicular bone
Adhesions of DDFT
Erosion of articular cartilages of navicular bone
Bursitis of navicular bursa
Caused by: Hereditary: heavy horse + small feet
Improper trimming: long toe/short heel

Question 6

Foot rot…?

Answer 6

Caused by dual bacterial infection
Most common in sheep/goats
Contagious!
Can be benign ->affect only skin between toes
Can be virulent -> bacteria rapidly under-run hoof and separate hoof horn from foot

Question 7

Define unsoundness

Answer 7

deviation of form or function -> useless

Question 8

Define blemish

Answer 8

Detracts from appearance but not function

Question 9

Define physitis

Answer 9

inflammation of physis

Question 10

Name & outline some conformational defects

Answer 10

Base narrow -> feet closer together at ground than origin at chest -> bear weigh unevenly -> OA (common in QH)
Base-wide -> opposite to base narrow -> stress on medial aspect of legs -> OA

Question 11

Define osteochondrosis

Answer 11

Disruption of normal ossification & differentiation of growing cartilage

Question 12

Define osteochondritis

Answer 12

inflammation & necrosis of cartilage due to osteochondrosis

Question 13

Failure of young bone to mineralise due to disturbed epipheseal growth = ?

Answer 13

Rickets in young animals

Osteomalacia in adult animals

Question 14

Name & describe a developmental bone disorder

Answer 14

Dyschondroplasia (osteochondrosis) -> disease of synovial joints due to disturbance of ossification of cartilage -> lesions articular, epiphyseal & metaphyseal growth-plate regions of long bone
Abnormal chondrocyte dev. -> ossification of cartilage -> thickening & weakening abnormal bone & cartilage. Trauma/exercise -> further damage -> separation of abnormal bone & cartilage from surrounding tissue -> osteochondritis dessicans (OCD) fragment form flap or detach in joint

Question 15

Causes of dyschondroplasia?

Answer 15

genetic, bio-mechanical trauma, low exercise, obesity, bad nutrition

Question 16

Prevention of dyschondroplasia?

Answer 16

Avoid fast growth
Avoid sudden growth after no growth
Avoid getting fat
Control exercise early years

Question 17

Compound fracture

Answer 17

broken across entire width of bone

Question 18

Greenstick fracture

Answer 18

small, slender crack or splinter on one side

Question 19

Physeal fracture

Answer 19

at junction of epiphysis or diaphysis

Question 20

Comminuted fracture

Answer 20

smashed -> smaller fragments (heals slower)

Question 21

3 main phases of fracture repair?

Answer 21

Inflamm
Reparative
Remodeling

Question 22

Inflammatory phase…?

Answer 22

1st 2-3 weeks
Chemical messengers mediate inflamm reaction
critical for reparative phase
Cellular mechanisms activatedfor repair & protection from infection
If inflam response impaired -> healing compromised

Question 23

Reparative phase…?

Answer 23

Susceptible to mechanical factors
Periosteal & endosteal callus form interfragmentory stabilisation
Bone union in intramembraneous & endochondral ossification
2-12 months
Utilises: fracture fixation, stabilisation

Question 24

Remodelling phase…?

Answer 24

During & after reparative phase
Avascular & necrotic regions replaced by Haversian remodelling
Malalignment of fragments corrected

Question 25

Fracture healing occurs/does not occur when...?

Answer 25

broken ends touch/excessive separation of fragments with fibrous tissue

Question 26

Describe process of fracture healing

Answer 26

Fracture -> blood vessels rupture -> release blood around broken bone -> clot ->2-3 days undifferentiated cells turn into fibroblasts & chondrocytes. Fibroblasts -> fibrous network between broken bone, Chondrocytes -> fibrocartilage -> callus formed Osteiod tissue fills gaps & fills marrow cavity Splint is formed Calus mineralised -> true bone Healing process completed reorganising callus forming typical bone shaft with marrow When bone used -> functional orientation of callus begins