Exam 1 - Lecture Flashcards
Kinematics
Motion of the body without external forces
3 different types of arthokinematic movements
spin, roll, glide
closed chain
distal end is fixed, proximal end is moveable
Osteokinematics
Motion relative to bones
arthorkinematics
motion relative to joints
Rotational Movement
motion spins around an axis of rotation and travels in an angular motion
axis of rotation location
perpendicular to the plane of movement and through the convex surface of a joint
open chain
distal end is moveable, proximal end is fixed
Typical movement in osteokinematics
rotation
what relative motion is most common?
open chain
typical movements in arthrokinematics
linear
Translational movements
move in a linear motion in parallel
rule for degrees of freedom
1) They are paired, therefore always even.
2) 0, 2, 4, 6 degrees are allowed
3) for every one ostero degree there is one artho degree
2 types of relative motion
open chain and closed chain
why are closed chained movements good?
- heavy loads/resistance
- maximum accuracy and precision
- minimize probability of overloading
degrees of freedom
the type and amount of movement allowed at a joint
Why are open chained movements good?
- low resistance/load
- max speed and displacement
Two types of joints
synarthoroses and diarthroses
things that are sometimes present in synovial joints
- intra-articular discs
- fat pads
- bursa
- labrum
- synoival plica (fold in synovial membrane)
synarthoroses
highly stable, inmoveable joints, fixed
7 elements of a synovial joint
1) blood vessles
2) Sensory nerves
3) synovial fluid
4) articular cartilage
5) synovial membrane
6) joint capsule
7) ligaments
types of synarthoroses
1) Fibrous - ie cranial sutures
2) cartilaginous - sternal angle joint, pubic symphysis
types of diarthroses
synovial joints
closed pack
- maximum congruency of articular surfaces
- maximum tightness of joint caps and ligaments
- high stability
- Intra-articular space minimal
- not easily distracted
- locking mechanism engaged
- effective in weight-bearing (decreased musle load)
ovoid vs sellar surface
ovoid - convex surface
sellar - convex and concave
why is convex and concave joint relations important?
1) improves congruency
2) increases articular surface area
3) guides motion
rules of convex/concave and concave/convex
-conVEX on conCAVE opposite roll and glide
(vex on cave not the same)
-concave on convex same roll and glide
diarthroses
freely moveable joint along mulitple planes
appling the CC rules (steps)
1) identify moving bone
2) determine moving bone joint surface (convex or concave)
3) locate axis of rotation
4) determine movements
two types of joint positions
closed pack and loose pack
open pack
- minimal congruency of joint surfaces
- minimal tightness of joint caps and ligaments
- low stability
- not good for weight bearing (muscles engaged)
- locking mechanism not engaged
- intra-articular space maximized (more synovial fluid)
- least stable
- easily distracted
perimysium
outter layer of muscle fascile
what determines range of excursion?
number of sarcomeres
endomysium
outter layer of muscle fiber
what are muscle fibers?
muscle cell (structual unit)
purpose of muscles
- produce locomotion by putting forces on joints
- utilize lots of energy
- control movement
- stablize and protect joints
what determines max force generation of muscle?
net cross sectional area of sarcomeres
bigger cross section of sarcomeres = ?
more force production of muscle
epimysium
outter layer of whole muscle
possible exceptions to the CC rule
1) deep concavity
2) axis of rotation through both articular surfaces (SPIN)
3) plane joints
longer muscles = ?
more excursion/contractility
characteristics of parallel
- less force production due to less muscle fibers
- more excursion and more ROM
- increased muscle shortening speed
muscle determinates of force
muscle architecture and muscle fiber type
what are sacromeres?
contractile unit in myofibril
pennation
muscle faciles attach obliquely to its tendon
characteristics of pennation
- more force production due to more muscle fibers in one area
- less excursion and less ROM
- decreased muscle shortening speed
parallel architecture
fasciles run parallel to force generating axis
slow oxidative fibers
- high aerobic capacity
- slow sustained force production
explain muscle length and tension relationship
- extreme lengthening = decreased tension production
- extreme shortening = decreased tension production
- optimal length = muscle generates greatest force
fast glycolytic fiber types (type IIb)
- high anaerobic capacity (no O2)
- quick, powerful, strong force
fast oxidative glycolytic fiber types (type IIa)
- intermediate characteristics
- use both anaerobic and aerobic systems
Active insuffiency
muscle is too short to produce functional amounts of force across 2 or more joints
-ie placing hip in full extension with knee fully flexed and trying to perform a hamstring contraction
insufficeny can lead to
muscle pulls and strains
isometric muscle contraction
muscle pulling force causes muscle to stay the same
adaptations of skeletal muscles
- hypertrophy
- atrophy
- changes in physiological length
- change in metabolic capacity
eccentric mucle contraction
muscle pulling force causes muscle to lengthen
concentric muscle contraction
muscle pulling force causes muscle to shorten
when do we often use eccentric muscle contraction?
going against gravity
how does muscle fiber types affect actions of muscles?
tonic - slow contraction and long durability
phasic - fast contraction and short durability
how does muscle force couples affect actions of muscles?
2 or more muscles working in different linear directions to produce same rotation direction
-ie shoulder girdle muscles to produce upward or downward rotation of scapula
how does muscle synergists affect actions of muscles?
- prevent unwanted movements at intermediate joints
- promote same action as agonists
hypertrophy
increased volume muscle fibers (number of cells)
results of hypertrophy
increased strength
passive insuffiency
muscle is too long to produce functional amount of force
-ie maximum wrist flexion lengthens finger extensors prohibiting the flexion of fingers
how does muscle morphology/geometry affect actions of muscles?
O and I pull direction
atrophy
decreased volume of muscle fibers (numbers of cells)
results of atrophy
decreased strength
Anatomy of an IVD
Nucleus pulposa, annulus fibrosus, vertebral end plates
job of nucleus pulposa
- soft inner material of disc
- shock absoption
composition of nucleus
- prosteoglycans
- type II collagen (15-20%)
- elastin fibers
job of annulus fibrosis
able to resist forces due to collagen fiber orientation
composition annulus fibrosis
- collagen fibers 50-60%
- perpheral layers consisit of types I and II collage
- 15-20 layers around the nucleus pulposa
what is the fiber orientation of the annulus fibrosis?
fibers are orientated 65 degrees from vertical axis with adjacent layers oriented in opposite directions
Where is the blood supply located for the disc?
in the peripheral layers
job of vertebral end plates
- provide strength and stability
- protect function and structures of the discs
describe the normal disc load transmission
NP and the AF are WB and transmit load to vertebral end plates
where is peak stress at on the disc?
posterior inner annulus
what part of the disc is not load bearing?
outtermost annular fibers
how is the load spread amongst the parts of the disc?
uniformly across inner anterior annulus and nucleus
describe axial compression
-WB loads cause axial compression
Leads to: disc space narrowing, disc budlges rapidly, vertebral bodies become closer, leads to disc dehydration
process of disc dehydration timeline
- 1.5 mm first 2-10 minutes
- 1 mm/hour following initial 10 minutes
- Plateau @ 90 minutes
- 16 hour day may lead to a 10% reduction in height and 16% reduction in volume, person may be 1-2% shorter at end of day
How is the vertical vertebral column stabilzed?
joints and ligaments
what is the spine susceptible to?
displacement via gravity and asymmetrical WB
what do trunk muscle do?
work to correct displacements
what determine which muscles are recruited for the spine?
dependent of displacement, head position, trunk sway, functional activities
What happens during standing for the trunk muscles?
trunk muscles vary from demonstrating NO to INTERMITTENT to SLIGHT CONTINOUS activity
what is line of gravity?
passed though the center of gravity, typically anterior to S2
What does the LOG determine?
muscle activation patterns
