Biomechanics: Vocab N Stuff Flashcards
Define mechanics
study of forces and motions produced by their actions
What does statics deal with?
factors associated with nonmoving systems
What does dynamics deal with?
factors associated with moving systems
Define kinetics
the forces causing the motion of the body
Define kinematics
time, space, and mass of the moving system
Define osteokinematics
bones moving in space in regard to joint surface
Define arthrokinematics
the manner in which joint surfaces move in relation to each other (concave)
Define vector
quantity having both magnitude and direction
Define scalar
quantity having only magnitude
Define inertia
a change in motion in either speed or direction
What is a force?
a type of vector
Define linear force
in a linear 2-force system, the forces act on the same line in the same or opposite direction
What is the vector loop equation for a four bar mechanism all heading to one point?
top half = bottom half
Define parallel forces
forces in the same plane and in the same or opposite directions
Define concurrent forces
two or more forces act from the same common point but pull in different directions
Define a force couple
two forces acting in an equal but opposite direction resulting in a turning effect
What is a couple?
something that has a tendency to rotate around points
What is the angle of pull?
the angle between muscle insertion and bone on which it inserts
What are the three components of force?
angular/rotary force, stabilizing force, dislocating force
Describe angular/rotary force
force of a muscle contributing to bone’s movement around a joint axis; greatest when muscle’s angle of pull is perpendicular to bone (90*)
Describe stabilizing force
degree of parallel forces generated on the lever (bone/joint) when the muscles angle of pull is less than 90*
Describe dislocating force
degree of parallel forces generated on the lever (bone/joint) when the muscle’s angle of pull is greater than 90*
Describe state of static equilibrium
all forces and moments acting on a body are in balance
Define center of gravity (COG)
balance point of a body around which the resultant torque due to gravity forces vanish
Define base of support (BOS)
part of body in contact with supporting surface
Define line of gravity (LOG)
imaginary vertical line that passes through the COG to center of earth
Define stable equilibrium
need to raise COG to disturb
Define unstable equilibrium
only a slight force needed to disturb
Define neutral equilibrium
COG is not raised or lowered to disturb
What are some ways to increase stability?
lower COG, lower distance from COG to BOS, wider base of support, greater mass, increase friction
Define flexion
a bending movement that decreases the angle between a segment and its proximal segment
Define extension
a straightening movement that increases the angle between body parts
How can you reason through the degrees of freedom?
how many joints would you have to freeze to stop it from moving
Degrees of freedom -> ball/socket or shoulder joint
3
Degrees of freedom -> pivot joint or top vertebrae
1
Degrees of freedom -> ellipsoid joint or radiocarpal
2
Degrees of freedom -> saddle joint or base of finger
2
Degrees of freedom -> condyloid joint or first knuckle
2
