Components of tissue
What are ligaments composed of? What motions do they resist?
They connect bone to bone
They are made up of heterogeneous structures, mainly type I collagen and elastin
They resist forces in many directions and the fibers are arranged in many directions
What is the difference between stress and strain?
Stress: is the amount of force applied to a tissue
Strain: is the amount of "stretch" a tissue can take from the force
What is the yield point on the stress strain curve?
The point where the tissues won't return to normal length (after the elastic region)
Define the movements of spin, roll, glide related to intra articular movements. Which is most common within the joint?
Spin: (radial notch of ulna)
Roll: condyles of the femur rolling on the tibia
Glide/slide: femoral condyles also have to slide forward when moving on the tibia to stay in contact with the tibia.
Most common: combo of roll and glide
Describe Wolffs law
Adaptation of bone to changes in stresses and loading
What are Tendons made of? What forces can they resist?
They connect muscle to bone
They are composed of mainly type I and III collagen (more type I to resist strong forces)
Resists motion in one direction
What is stiffness?
The resistance of a tissue to avoid deformation
The more stiff a tissue is, the harder it will be for the tissue to tear
What would happen to viscoelastic tissue when the rate of loading is increased? What happens when the tissue is heated?
If the tissue is heated, the strain of the tissue would decrease as temperature increases
What is the difference between osteokinematics and arthrokinematics?
Osteokinematics: Rotary movement of bony levers- movement described in a plane, axis or direction
Arthrokinematics: change in articular contact- roll, slide, spin
What are the 3 main joint categories? What are the categories for degrees of joint movement?
Fibrous, cartilaginous and synovial
Synarthrosis (little to no movement), Amphiarthrosis (minimal movement), Diarthrosis (freely moveable)
What is cartilage made out of? What is its biggest issue for healing?
Hyaline: Type II collagen>elastin lines ends of long bones, compressive forces feed cartilage structures
Fibrocartilage: Type I collagen> Type II, diffusion/exchange of nutrients through weight bearing
Both lack vascular blood supply, can't heal back to original
It is in all connective tissues
Elasticity: materials ability to return to original length or shape
Viscosity: materials resistance to flow
Behavior is dependent on time, rate and history
What are some differences between the synovial and fibrous layers of the joint capsule?
Synovial: inner layer
Fibrous: outer layer
Innervation and vascularization????
What happens if the CONCAVE joint segment is moving?
The rolling and gliding occur in the SAME direction
What are examples of a triaxial joint?
Ball and socket and plane joint, 3 degrees of freedom
Mainly Type I collagen and inorganic minerals
Organic: strength/flexibility
Inorganic: compressive
2 Layers: trabecular and cortical bone
What is "creep" response?
A deformation sustained overtime due to repetitive loading
Ex. lumbar disk deformation
Is a condyloid joint uniaxial, biaxial, or triaxial? How many degrees of freedom does it have?
Biaxial, 2 degrees of freedom
What is an open chain movement?
One end of the segment is free to move, the other end is fixed.
Ex.) Dart throwing
What are examples of a biaxial joint?
Condyloid and saddle joints, 2 degrees of freedom
What happens when cartilage undergoes compression? What factors determine the response and how do they affect it?
Compressive/loading forces feed cartilaginous structure
Diffusion/exchange of nutrients and waste through weight bearing
There is minimal blood supply to peripheral regions
What are the parts of the stress/strain curve? Explain each part.
Toe region: fibers uncrimp, about 2% of strain
Elastic region: fibers can stretch and return back to normal length, 2-4% strain
Plastic region: fibers stretch and DON'T return back to normal length, 4-6% strain, microscopic failure
Failure point: complete fiber tear, won't return to original length, macroscopic tear
What is the movement of the lever when the CONVEX end of the lever moves on the CONCAVE surface?
When the convex part is moving on the concave surface rolling and gliding happen in OPPOSITE directions
What is a closed chain action?
Both ends of the kinetic chain are fixed
Ex.) Squat
What are examples of a uniaxial joint?
Hinge and pivot joints, 1 degree of freedom