Exam 1 Flashcards
Vertebral body function
resist compressive load
Vertebral pedicle function
Transmit the bending forces from the posterior elements to the vertebral body
Vertebral lamina function
Transmit forces from the articular, transverse and spinous processes to the pedicles
Vertebral transverse procress function
Serve as muscle attachment and provide mechanical lever
Vertebral spinous process function
Serve as muscle attachment and provide mechanical lever; may also serve as bony block to motion
Vertebral foramen function
Combined with all segments, forms a passage and protection for the spinal cord
what does an intervertebral disc consist of?
- nucleus pulposus
- anulus fibrous
- vertebral end plate
what is the nucleus pulpous?
- “Pulp-like gel”
- 70-90% water
- jelly part of intervertebral disc
what is the annulus fibrosis?
- Fibrous outer ring
- 60-70% water
- Collagen and elastin arranged in 15 to 25 concentric layers
- Fibers oriented 65° from vertical
- band portion of intervertebral disc
what is the vertebral end plate
- Cartilaginous layer covering superior and inferior surfaces of the disc
- 0.6 to 1 mm of cartilage in adults, larger in children
- Strongly attached to annulus fibrosis but not the vertebral body
- can be apart of the bone
how much of force is transmitted through intervertebral disc?
80%
what in the intervertebral disc is capable of resisting distraction, shear, and torsion
anulus fibrosis
anterior longitudinal ligament
limits extension
- reinforces anterolateral portion of annulus fibrosis and anterior aspect of intervertebral joints
posterior longitudinal ligament
limits forward flexion
- reinforces posterior portion of anulus fibrosis
ligamentum flavum function
limits forward flexion
- particularly in lumbar area
interspinous ligaments
limits forward flexion
supraspinous ligaments
limits forward flexion
intertransverse ligaments
limits contralateral lateral flexion
what is coupling
consistent association of one motion about an axis with another motion around a different axis
coupling patterns vary based on…
- spinal structure
- spinal curvature
- orientation of articulating facets
- fluidity/elasticity/thickness of the disc
- extensibility of the muscles, ligaments, joint capsules
what do the inter body joints do
- determine magnitude of movement
- distribute load
- create space for movement and passage of spinal nerve roots
what do facet joints do
- determine direction of movement
2. influenced by geometry, height, and spatial disorientation
vertebral flexion is…
anterior tilt and anterior glide of superior vertebra
vertebral flexion results in ..
- widening of intervertebral foramen
- separation of spinous processes
vertebral extension is…
posterior tilt and posterior glide of superior vertebra
vertebral extension results in…
- narrowing of intervertebral foramen
- spinous processes approximate
vertebral lateral flexion is…
lateral tilt, rotation and translation of superior vertebra over inferior vertebra
vertebral lateral flexion results in…
- widening of intervertebral foramen on contralateral side
- narrowing on ipsilateral side
vertebral rotation
- varies by region
- rotation of inter body joint
- approximation/distraction at facet joint
what are the upper cervical vertebra
- occiput
- atlas
- axis
what are the lower cervical vertebra
C3-C7
atypical cervical vertebrae
- atlas
- axis
- C7
what is the function of the atlas
- cradles occiput
2. transmits forces from occiput to C-spine
what is the function of the axis
- transmits combined load of head/atlas to C-spine
2. provides axial rotation of head/atlas
Atlanto-occipital joint
between convex occipital condyles with concave superior facets of atlas
- synovial
antlanto-axial joint
between dens and anterior arch of atlas/transverse ligament
- synovial
AND
between inferior facets of atlas wit superior facts of axis
posterior Atlanto-occpital membrane continues to be..
ligamentum flavum
posterior Atlanto-axial membrane continues to be…
ligmentum flavum
anterior atlanto-occipital membrane continues to be…
anterior longitudinal ligament
tectorial membrane continues to be…
posterior longitudinal ligament
ligamentum nuchae continues to be…
supraspinous ligament
transverse atlanto ligament function
to prevent anterior displacement of C1 on C2
alar ligament function
limit lateral flexion and prevent distraction of C1 on C2
how are the cervical facet joints oriented
45 degrees off frontal and transverse planes
Describe what happens in the upper and lower cervical spine with protraction
upper cervical extension, lower cervical flexion
Describe what happens in the upper and lower cervical spine with retraction.
upper cervical flexion, lower cervical extension
what ligament limits rotation of AA joint
alar ligaments
what ligaments limits tilting of axis at AA joint with flexion
transverse lig
osteology of TMJ
condyle of mandible with articular eminence of temporal bone
classification of inferior TMJ
simple hinge
classification of superior TMJ
functions as a gliding joint
function of lateral TM ligament
stabilize lateral portion of capsule
- help guide movement of condyle during opening
function of stylomenadibular ligament
weakest of the three ligaments with questioning function
function of sphenomandibular ligament
swinging hinge that suspends the mandible
What is the normal resting position of the TMJ and what muscle maintains that position?
o Lips closed and teeth several millimeters away
o Maintained by temporalis muscle
which thoracic vertebrae have full costal facets
T1, 10, 11, 12
what articulation makes up the costotransverse articulation at T1 - T6
concave coastal facet of transverse process
WITH
convex costal tubercle of rib
what are some causes of hyperkyphosis
- trauma
- abnormal growth/development of vertebrae
- severe DDD
- marked osteoporosis
define functional scoliosis
caused by muscle shortening
define structural scoliosis
not muscular, structural
what structures resist shearing force in the lumbosacral angle
Intervertebral disc, facet joint capsules, ALL and iliolumbar ligaments
where does spondylolisthesis occur?
most commonly at L5/S1 secondary to angulation of this segment
anterior SI joint
type
synovial joint with articular surfaces
posterior SI joint
type
syndesmosis with tuberosities
List and describe the 4 ways to reduce force required of the lumbar extensors when lifting.
o Reduce velocity of lifting
o Reduce magnitude of external load
o Reduce length of EMA
o Increase length of IMA
define nutation
sacral promontory moves anteriorly and inferiorly and sacral apex moves posteriorly and superiorly
- occurs by anterior sacral-on-iliac rotation, posterior iliac- on-sacral rotation
standing
define counternutation
sacral promontory moves posteriorly and superiorly and sacral apex moves anteriorly
- Occurs by posterior sacral-on-iliac rotation, anterior iliac- on-sacral rotation
laying down
define anterior pelvic tilt
ASIS and pubic symphysis move inferiorly
define posterior pelvic tilt
ASIS and pubic symphysis move superiorly
what is the primary function of lumbar spine
to provide support for weight of the upper body
- designed to withstand compressive loads applied with muscle contraction
what is the primary function of pelvis
to transmit force of vertebral column to lower extremities
- relieve stress on pelvic ring created by movement of trunk and lower extremities
deine kinematics
branch of mechanics that describes the motion of a body, without regard to forces or torques
define kinetics
branch of the study of mechanics that describes the effect of forces on the body
define transition motion
Linear motion in which all parts of a rigid body move parallel to and in the same direction as every other part of the body
define rotation motion
Motion in which an assumed rigid body moves in a circular path around some pivot point
measured in degrees or radians
what is the convex-concave relationship
- improves joint congruency
- increases surface area for dissipating contact forces
- helps guide motion between bone
define roll
multiple points on multiple poitns
define slide
single point on multiple poitns
spin
single point on single point
_____ directs the osteokinematic path
roll
define force
push or pull that produces, arrests or modifies movement
define load
force that acts on body
what regions make up the elastic region of stress strain curve
toe and linear
what is the toe region of stress strain curve
area that must be drawn taut before tension is measured
what is the linear region of stress strain curve
after slack is taken up; linear relationship between stress and strain
what makes up the plastic region of stress-strain curve
yield point, ultimate failure point
what is the yield point
elongation occurs
beyond physiologic range
what is the ultimate failure point
point where tissue is partially or completely separated (failure point for healthy tendon 8-13% beyond prestreched length)
define viscosity
resistance to flow
(depends on proteoglycans and water composition of the tissue)
- Tissues with high viscosity=high resistance to deformation
define elasticity
ability to return to original length or shape after removal of deforming load (depends on collagen and elastic content as well as organization of the tissue)
what are first class levers designed for
balance
ex. head and neck extensor muscles
what are second class levers designed for
power
- calf producing torque to stand on tiptoes
what are third class levers designed for
speed and distance
most common
ex. elbow flexors
what is a force couple
- synergist
- 2 or more muscles simultaneously produce force in different linear directions but produce torque in the same direction
steepness of the passive length-tension curve depends on…
- muscle architecture
- amount and type of supporting CT
passive tension serves to…
stabilize or move a joint
what is the force-time relationship
- The force generated by a muscle is proportional to the contraction time
- The greater the contraction time the greater the force up to maximum contraction
what are the components of CT
- fibrous proteins
- ground substance
- cells
what is a contractile protein
it shortens the muscle fiber and generates active force
- actin and myosin
what is the purpose of non-contractile proteins
- support the structure of muscle fiber
- titin: provides passive tension
- desmin: stabilizes alignment of adjacent sarcomers
what are the extracellular CT in muscles?
collagen and elastin
what is a fusiform muscle
has parallel fibers attaching to central tendon
- longer
- greater ROM
what is a pennate muscle
oblique fibers approach central tendon
- shorter
- greater force production
define synergist
muscles that COOPERATE during the execution of a particular movement
define agonist
most directly related to initation and execution of a particular movement
what is the advantage of an isokinetic movement?
allows the ability to adjust resistance throughout ROM of the muscle to account for stronger/weaker areas
what can passive tension be attributed to?
elastic forces produced by non-contractile elements
what are the components ALWAYS found in a synovial joint?
- articular cartilage
- articular capsule
- synovial membrane
- synovial fluid
- ligaments
- blood vessels
- sensory nerves
what is the articular cartilage of a synovial joint?
covers articular surfaces
what is the articular capsule of a synovial joint?
composed of CT that encloses the joint
- fibrous layer
- synovial layer or membrane
what is the synovial membrane e of a synovial joint?
internal layer of articular cartilage
what is the synovial fluid of a synovial joint?
produced by cells within synovial membrane
- coats surfaces of joints to decrease friction and provide nourishment
what is the purpose of ligaments within a synovial joint?
to protect from excessive movement
what things are SOMETIMES found in a synovial joint?
- intra-articular discs
- peripheral labrum
- fat pads
- bursa
- synovial plica
what is the primary function of dense connective tissue?
to resist tension
what is the primary function of articular cartilage
to distribute and absorb joint forces and reduces joint friction
primary function of fibrocartilage
supports and mechanically stabilizes joints, dissipates loads and guides complex arthrokinematics
what is the primary function of bone
rigid support to the body and systems of levers for muscles
newtons first law :
law of inertia
define newtons first law
a body remains at rest or at a constant angular velocity around an axis of rotation unless compelled by an external torque to change its state
where does the center of mass lie in a human
anterior to 2nd sacral vertebra
what is the relationship between the mass moment of inertia and angular velocity
a decreased mass moment of inertia will increase angular velocity
newtons second law :
law of acceleration
define newtons second law
The angular acceleration of a body is directly proportional to the torque causing it, take places in the same rotary direction in which the torque acts and is inversely proportional to the mass moment of inertia of the body
newtons 3rd law :
law of action-reaction
define newtons 3rd law
for every torque there is an equal and opposite directed torque
what is an electrogoniometer
measures joint angular rotation during a movement
what is an accelerometer
measures acceleration fo either individual segment or whole body
TMJ disc displacement with reduction
click during mandibular depression and elevation
- reciprocal click
disc displacement without reduction
disc does not relocate due to mechanical obstruction
- only one click
the later the click occurs in opening phase…
the greater the degree of dislocation
