Basic Concept 2 Flashcards
What are the two basic structure and function joints?
Synarthrodial and diarthrodial
What is arthrokinematics?
The motion that occurs between the articular surfaces of a joint.
What is synarthrodial?
Connective tissue holding bony components together.
What are the two types of synarthrodial joints?
Fibrous and cartilaginous
What are the two types of fibrous joints?
Sutures-skulls
Syndesmoses-tibia/tibia
What are the two types of cartilaginous joints?
Symphyses-symphysis pubis
Synchondroses-first chondrosternal joint
What are diarthrodial joints?
Synovial joints that always contain a synovial membrane, fluid, articular cartilage and joint capsule.
What are the three different types of diarthrodial joints?
Uniaxial joints
Biaxial joints
Triaxial joints
What are the two types of uniaxial joint types?
Hinge joint-elbow
Pivot joint-proximal radioulnar
What are the three biaxial type joints?
Condyloid-metacarpophalangeal
Saddle-thumb carpometacarpal
Ellipsoid-radiocarpal
What are the two triaxial type joints?
Plane-carpometacarpal
Ball-and-socket-hip and shoulder joint
What are the two articular joint surface shapes?
Ovoid Saddle(sellar)
What is a ovoid articular joint shape?
One surface is convex and the other concave
What is a saddle articular joint shape?
Each surface has one convex and concave surface
What are the three different types of joint motion?
Roll
Slide/glide
Spin
What are the three principles of movement?
For a concave-on-convex surface movement, the concave member slides in the same direction as the movement
For a convex-on-concave surface movement, the convex member slides in the opposite direction as the movement
Rolling is always in the same direction of the bone movement
What is the instantaneous axis of rotation?
The axis of rotation at any particular point in the motion
Joint motion occurs as a result of what?
A combination of rolling and gliding
What is joint play?
Joint laxity that allows normal sliding, spinning, and rolling to take place. Typically not under voluntary control.
Joint play is considered what type of motion?
Accessory motion
If there is not enough joint play it results in what?
Loss of ROM
If there is too much joint play it results in what?
Loss of stability
What is hypermobility?
Excess motion in a joint due to failure of the bony or soft tissue structures to prevent the motion
What is hypomobility?
Loss of motion in a joint due to inability of the soft tissue to elongate or the presence of a bony block
What do the numbers mean on a joint mobility assessment scale?
0-no motion 1-hypomobility 2-slight to moderate hypomobility 3-normal 4-slight hypermobility 5-severe hypermobility 6-instability
What are the two types of joint positions?
Close-packed
Open-packed
What is closed-packed joint position?
Joint surfaces are maximally congruent and ligament and capsule are maximally taut
Very stable and powerful
What is open-packed joint position?
Any position other than closed-packed
The position where joint structures are most lax and joint cavity has the greatest volume.
Swelling
What angle is the most open-packed position?
30 degrees to allow for the most swelling.
What is open chain?
The ends of the limbs are free to move
Distal mobility on proximal stability
What is closed chain?
The ends of the limbs are fixed with movement higher up the chain.
Distal stability on proximal mobility
What are the two types of kinetic forces?
External
Internal
What are external forces?
Gravity
Wind
Water
Resistive devices
What are internal forces?
Pull of muscles
Pull of ligaments
Compression of bones
What is the forces of gravity?
Attraction of the mass of the earth for the mass of the object.
Earth’s gravity has a magnitude of 32 ft/sec2 or 9.8 m/sec2
Weight=mass X 32 ft/sec2
What is the center of gravity?
The hypothetical point at which all mass would appear to be concentrated and is the point at which the force of gravity would appear to act
What is another name for center of gravity?
Center of mass
What is the line of gravity?
Line of the pull of gravity on an object
Can be visualized as a plumbline extending from the COG to the ground
What is Anatomical COG?
Anterior to the second sacral vertebra
Changes position as the body segments are rearranged
What is segmental center of gravity?
Each segment of the body has its own center of gravity. When the segment moves, it may change the COG of the whole complex.
What is stability and center of gravity?
For an object to remain stable, the COG must fall within the base of support (BOS).
How do you improve stability?
Lower COG
And
increase base of support
What causes the relocation of COG?
Pregnancy
Carrying weight
Application of orthotic or prosthetic
Change of BOS
What is the action line?
The direction of the muscle pull
What is the lever arm?
The bone upon which the muscle acts
What is the angle of application?
The angle between the action line and the lever arm
What is torque?
The ability of a muscle to move a joint is measured by torque.
Torque(T)=force X moment arm (MA)
What is force?
The amount of pull the muscle can create
What is the moment arm?
The distance between the action line and the joint axis.
When is the muscle most efficient?
When it can produce the most torque; which is the point where the moment arm is greatest.
What act as anatomic pulleys?
Anatomic ridges
Tubercles
Sesamoids
What are the advantages of anatomic pulleys?
Changes the direction of the pull of the muscle
Deflects the action line away from the joint axis increasing the MA and torque
