1.Fracture biomechanics Flashcards
what is inorganic osteoid?
unmineralized bone made by osteoblast
osteoclast develops from which lineage?
monocytes
Describe an osteoclast
large, multinucleated cell
responsible for bone resorption
produce acid locally which helps with bone resorption
what makes up the organic ECM?
type 1 collagen and some ground substance such as proteoglycans
Know the macroscopic anatomy of the bone
-epiphysis
-metaphysis
-diaphysis
epiphysis is mostly cartilage- at the articular surfaces
where is cortical bone found
cortical bone aka compact bone is found at the shaft of long bones
what are some properties of cortical bone? density? cellularity?
how does it develop?
cortical bone is acellular and highly dense
it develops in proportion to stress
bone surrounds blood
where is trabecular bone found?
found on long bones, axial skeleton
its on the ends of the long bones
very porous, rich in nutrients/blood
blood surrounds bone
what connects the periosteum to the cortical bone?
sharpeys fibers
ECM made up of organic and inorganic substance, what are they
organic- type 1 collage
inorganic-hydroxyapatite
hydroxyapatite is laid down by ___ as ______
how Is it mineralized?
osteoblast as unmineralized osteoid
alkaline phosphatase -enzyme
What is significant about the primary and secondary ossification centers in relation to bone fractures
this is at the site of the growth plate/physis
this is usually where the bone fractures occur bc its the weakest area, and specifically at the zone of hypertrophy
what are some functions of bones
protective- ribs and skull
movement- muscles attach to it
shape- provides the body with a figure
blood cell production- BM RBC/WBC
IO vs EO
intramembranous ossification: no cartilage template
EO- endochondral ossification has a cartilage intermediate
what is an osteon, where is it found
its mineralized osteoid that becomes osteon
-this is cortical bone
is found at the metaphysis and diaphysis, its strongest at the diaphysis
explain load deformation and stress-strain curve
bone has an elastic phase, theres a yield point where it becomes plastic and can not deform- if increasing load at the plastic phase the bone will break
what is tension force and what type of fracture occurs
this is when bone is being pulled in opposite direction
transverse fracture
what is compression force and what type of fracture occurs
bone compressed
what is shearing force and what type of fracture occurs
shearing is forces applied from opposite sides
fracture can be oblique
what is torsion force
twisting of the bone
spiral or long oblique
what fracture would you expect with a compression and bending force
transverse with a butterfly piece
what fracture would you see with a bending force
transverse with a small butterfly
with load and deformation curves- what happens to the curve when the loading rate is extremely fast?
bone is less elastic- becomes plastic quickly both of these phases are short lived and bone fails
slower loading rate allows for the bone to remain elastic and not fail as easily/quickly
open vs closed fracture whats the differences
open fracture has exposed bone to the outside-
closed fracture- no bone has pierced through soft tissue
simple vs comminuted
comminuted >2 pieces. causes by greater forces such as HBC or gun wound
simple: 2 piece fracture, usually transverse or oblique/spiral
anatomic location refers to what when describing the fracture
right or left
metaphysis,physis etc
fracture line:transverse or oblique etc
salter harris classification
Type I: Physis- only physis involved, good prognosis
Type II: Metaphysis, good prognosis
Type II: Epiphysis- poor, involves articular surface
Type IV : Both epiphysis and methaphysis, poor prognosis
Type V: Crushing forces, leading to angular deformities
type 1 open fracture
fractured bone penetrates the skin from within, so the fracture caused the wound
type 2 open fracture
wound connected to the fracture
wound >1cm
type 3 open fracture
IIIa
IIIb
IIIc
high energy trauma, soft tissue and bone loss
3a-minor plastic procedure if any
3b- soft tissue remaining no enough to close wound
3c- blood supply compromised, may need amputation
