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56 Cards in this Set
- Front
- Back
Kinesiology |
the study of the anatomical, biomechanical and physiological interactions within the musculoskeletal system; inspired by work of Leonardo DaVinci |
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Kinematics |
describes motion of a body without regard for the forces/torques acting on the body |
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Translation |
describes linear motion of a body |
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Rotation |
describes angular motion of a rigid body about some pivot point (axis) |
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Goniometer |
tool used to measure/quantify rotation of joints in degrees |
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Axis of Rotation |
pivot point for angular motion; always perpendicular to the plane of motion |
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3 Axes of Rotation |
1. vertical 2. medial-lateral 3. anterior-posterior |
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Flexion/Extension |
rotary motion that occurs in the sagittal plane about a medial-lateral axis of rotation |
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Abduction/Adduction |
rotary movement that occurs in the frontal plane about an anterior-posterior axis of rotation |
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External/Internal Rotation |
rotary movement that occurs in the horizontal plane about a vertical axis of rotation |
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Degrees of Freedom |
Depicts the number of independent movements allowed at a joint corresponding to angular motion in the 3 cardinal planes |
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Accessory Motions |
the small degree of translation that can occur in synovial joints and occurs in linear directions (e.g. anterior-posterior, superior-inferior); the amount of this motion is used to test for the integrity of ligaments and to detect joint instability |
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Open Kinematic Chain |
when the distal segment of an extremity rotates on the proximal segment; ex: bringing hand to mouth, reaching forward with UE, putting arm behind back, crossing leg, advancing limb during gait |
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Closed Kinematic Chain |
when the proximal segment of an extremity rotates on the distal segment; ex: squatting down, push/pull ups, standing up |
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Arthrokinematics |
describes the motion that occurs between the articular surfaces of joints during movement |
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Normal Joints |
remain centered and in full opposition during movement |
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1. Stabilizing function of muscle 2. Articular structure/configuration 3. Tension in periarticular connective tissue |
What 3 factors ensure the stability of joints? |
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Roll & Slide |
during movement the articular end of the rotating bone rolls, and the articular surface simultaneously slides, against the opposing bone's articular surface |
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Slide |
_______ is not the same as translation! |
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Closed-Packed Position |
position where joint surfaces "fit best" (i.e. maximally congruent); occurs near end of ROM where capsuloligamentous structures are taut |
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Loose-Packed Position |
all positions other than the closed-packed position |
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Kinetics |
describes the effect of forces on a body; a force can be a push or a pull that can produce, arrest or modify movement; forces provide the ultimate impetus for movement and stability of the body; forces that act on the body can be internal or external |
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External Forces |
gravity, external load or physical contact from others (e.g. therapist doing manual muscle test) |
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Internal Forces |
active or passive forces produced within the body; muscle activation, tension in periarticular connective tissues |
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Gravity |
the attraction of the mass of the earth for the mass of objects; most consistent force encountered by the body |
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Center of Gravity |
point of application of gravity (line of gravity); during movement it changes constantly |
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Effects of Gravity |
can be manipulated by changing the position of your body or by moving in a plane that is the same as the direction of gravity |
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Stability and Center of Gravity |
for an object to be stable, the line of gravity must fall within the base of support; the closer the center of gravity is to the base of support, and the larger the base of support is, the more stable the object is |
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Torque |
a force acting at some distance from the axis of rotation of a joint is converted into a ______, which then has the potential to cause rotation of the joint; a product of a force and its moment arm |
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Moment Arm |
the distance between the axis of rotation and the application of force |
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Equation for Torque |
T = F x MA |
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Internal Torque |
the product of the internal force (muscle) and the internal moment arm (the muscle's moment arm) |
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External Torque |
the product of the external force (gravity, weights, etc.) and the external moment arm |
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Composition of Forces |
total force of all the fibers of a muscle is often represented as a single line of action (resultant muscle action line) |
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Rotation |
a portion of the overall force acts perpendicular to the long axis of the bone and will therefore contribute to ________ of the joint |
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Compression |
a portion of the overall force acts parallel to the long axis of the bone and will almost always cause __________ of joint surfaces |
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Compressive |
________ force is almost always much larger than the rotational component |
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Muscle action at a joint |
the potential of a muscle to create a torque (i.e. cause rotation) in a particular direction and plane |
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Steps in analyzing actions of a muscle |
1. determine the degrees of freedom at the joint 2. determine how the muscles line of action crosses the axis(es) of rotation of the joint |
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Lever |
a rigid bar suspended across a pivot point |
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Leverage |
the relative moment arm length possessed by a particular force |
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first class lever |
axis of rotation is between the opposing forces |
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second class lever |
axis of rotation is located at one end of a bone; the internal force (muscle) always possesses greater leverage than the external force |
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third class lever |
as opposed to the second class, the external force always has less leverage than the internal force (muscle); most common lever in the MSK system |
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Mechanical Advantage of MSK Levers |
the ratio of the internal moment arm to the external moment arm; measure of the efficiency of the lever |
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Muscular System Trade Off |
muscle pays the price in force requirement by acting so close to the joint's axis (lots of force required for a small amount of weight); the advantage is that we have a much larger potential for rotation (we can make a full fist) |
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Loads applied to MSK system |
normal tissue is able to adequately resist changes in its shape within a limit (disease or trauma can change this limit) |
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Stress |
measure of the internal resistance generated as a tissue resists its deformation (e.g. while lengthening); types: compressive, tensile, & shear |
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Strain |
magnitude of tissue deformation; ratio of tissue's deformed length to its original length |
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Stiffness |
the ratio of stress/strain in connective tissue |
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plastic deformation |
if the limit for the physiologic range in which connective tissue can tolerate stress/strain is exceeded, __________ occurs and the CT will be irreversibly damaged and eventually fail |
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Viscoelasticity |
most tissues in the body exhibit this property; tissues exhibit changes in the stress-stain curve as a function of TIME (rate & duration); mechanical properties of connective tissue change depending on how fast or how slow (rate) length change occurs; faster the stretch, the greater the resistance, slower the stretch=less resistance |
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Creep |
this property dictates that if stress is held constant, the strain increases with time; forms the basis for the use of dynamic splints to restore joint mobility |
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Dynamic Splint |
stress on the tissue is held constant (from the pull of a rubber band) for 30 mins; over that TIME, the amount of strain (i.e. change in length) in the tissue will increase |
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Stress Relaxation |
this property dictates that if strain is held constant, the stress decreases over time; forms the basis for the use of static progressive splints to restore joint mobility |
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Static progressive splint/cast |
set the strain rate (i.e. degree of elongation) to a point and leave it 30 mins; over that TIME, the amount of stress (i.e. internal resistance to elongation) in the stretched tissue will decrease |