MSK 1 Flashcards
what is the weakest place in growing bones?
the growth plate or physis
what is the one thing that a fracture MUST have in order to heal?
adequate blood supply
young animals often get what kind of fractures?
along the growth plate (different salter harris classifications)
what is the most common type of salter harris fracture in young animals?
type II along physis and into metaphysis
angular limb deformities are common in what kind of animals?
fast growing animals like dogs and horses
what are thw two types of angular limb deformities?
valgus: lateral deviation or splay legged
varus: medial deviation or bow legged
you are brought a cute rescue pittie mix with bowed legs and the new owner wants to know what it is and what caused it. You tell them…
the dog has varus or medial deviation, form of angular limb deformity, and it is caused most commonly by asymmetric damage to the growth plate (one side closes and the other grows), can also be caused by malposition in utero, joint laxity, hypothyroidism, malnutrition, or sometimes we aren’t sure why
name these conditions
top is valgus, bottom is varus, both forms of angular limb deformities
this is from a puppy. what is the arrow pointing to and why is it significant?
it is pointing to an area where the growth plate of the radius dissapeared, so no further growth can occur at this site. this likely happened because of some trauma to the radial growth plate in that location
fractures occur when the ______ exceeds the _____
mechanical force
bone strength
define a fracture
a break/rupture resulting in a physical discontinuity in a bone
what are the two ways in which fractures are classified?
traumatic (forces break a normal healthy bone) and pathologic (forces break an unhealthy or diseased bone)
list the ways to classify a fracture
open/closed
displaced or not
comminuted
transverse/oblique/spiral/linear
location (proximal, distal, midiaphyseal)
name the bone
what is an avulsion fracture
when a ligament pulls bone away from a site of insertion
what is a greenstick fracture?
where one cortex is broken but the other side is not, happens in young animals (think of a green twig breaking and only one side breaks while the other stays in tact)
what are the 5 steps in fracture healing?
- hematoma
- fibrous tissue
- woven bone and cartilage laid down
- soft callus or primary callus forms
- hard callus or secondary callus forms (woven bone to lamellar bone)
list some reasons for non-union fractures
inadequate blood supply, instability/excessive forces or motion, infection, pathologic underlying disease, malnutrition, necrotic tissue like a sequestrum
what does the word osteodystrophy mean? What causes this? What is a common result?
abnormal bone growth
caused by nutritional or hormonal imbalances, toxicities, etc
common result is pathologic fractures and pain
osteodystrophy is more commonly seen in what kind of animal?
growing animals
the top arrow is pointing to what? What is the cause of this lesions and what is the pathogenesis?
it is showing a growth arrest line (just above the growth plate), caused by debilitating disease or malnutrition. the trabeculae in the metaphysis are abnormally algined so that they are parallel to the physis instead of perpendicular
Pathogenesis: inciting cause–>long bone growth stops–>abnormal osteoclast activity–>lines are carried into metaphysis as growth resumes
what is seen here and what does this indicate?
serous atrophy of fat, indicating the animal was either anorexic or in starvation, the medullary fat has become gelatinous and see through rather than white and opague. note also the cortex is thinner than normal