Adapted from Kapandji Extension IVF decreases in size AL Lig. stretched PL Lig. and Lig Flavum...
If you can't read please download the document
Adapted from Kapandji Extension IVF decreases in size AL Lig. stretched PL Lig. and Lig Flavum relaxed Supra and Interspinous Ligs. relaxed Spinous Processes
Adapted from Kapandji Extension IVF decreases in size AL Lig.
stretched PL Lig. and Lig Flavum relaxed Supra and Interspinous
Ligs. relaxed Spinous Processes brought together Nucleus Propulsus
pulled/pushed forward Anterior Annulus tensed Posterior Annulus
compressed Articular Facets compressed, capsules relax Flexion IVF
increases in size AL Lig. relaxed PL Lig. and Lig Flavum stretched
Supra and Interspinous Ligs. stretched Spinous Processes separate
Nucleus Propulsus pulled/pushed backward Anterior Annulus
compressed Posterior Annulus tensed Articular Facets unloaded,
capsules stretch The Vertebral Motion Segment EXTENSION
Slide 2
MOVEMENTS OF THE SPINE Functional motions Normal and typical
motions Usually occurs diagonal or oblique to cardinal planes
Non-functional motions Motion in one of the cardinal planes Usually
used for evaluation Notepack: page 21
Vertebral Combined Motion Kinematics Notepack: page 23 Source
Gary Gorniak, PT, PhD Note: TOTAL ROM is not the sum of segmental
ROMs
Slide 7
The Intervertebral Discs LOADS: 80% DISC *** 20% POSTERIOR
STRUCTURES (JOINTS, LAMINA) *** WWTIVDD? 1.Bind vertebral bodies
2.Permit movement between vertebra 3.Transfers loads from one
vertebra to another
Slide 8
Annulus Fibrosus 6 10+ circular rings of fibrocartilage
Collagen fibers in layers surrounding nucleus pulposus are arranged
loosely Collagen fibers in the outer layers are densely packed and
run obliquely between the vertebral bodies Collagen fibers in the
outer-most 1-2 layers have a crossing herringbone pattern which
makes these layers strong in resisting tension WHAT FORCES COULD BE
RESISTED BY THE ANNULUS ALONE? Posterior 65 to 70 0
Slide 9
Nucleus Pulpulsus Pulp-like gel located in the mid to posterior
part of the disc. 70-90% water thickened with large branched
proteoglycans, type II collagen, elastic fibers, and non- collagen
proteins. (collagen mesh in a mucoprotein gel) Functions: Force
transmitter Equalizes unit stress in all directions to the annulus
fibrosus Absorbs and retains water Nutrition conduit
Slide 10
Nucleus Propulsus lies central to slightly posterior Nucleus
Propulsus lies more posterior Disc Structure in the Different
Vertebral Regions Nucleus Propulsus central to slightly posterior
2/3 1/3 1/2
Slide 11
REGION FLEXIONEXTENSION SIDE BEND RIGHT ROTATION RIGHT ATLANTO
OCCIPITAL ROC and LOC roll anteriorly and glide posteriorly ROC and
LOC roll posteriorly and glide anteriorly ROC and LOC roll right
and glide left ROC moves slightly back and LOC moves slightly
forward ATLANTO AXIAL RF and LF of Atlas moves forward on Axis
facets RF and LF of Atlas moves backward on Axis Atlas slides right
RF of Atlas moves back and LF moves forward C2/3 T2/3 RF and LF
slide up and forward RF and LF slide down and back RF slides down
and back and LF slides up and forward RF slides down and back and
LF slides up and forward THORACIC T3/4 T11/12 RF and LF slide up RF
and LF slide down RF slides down and LF slides up RF distracts and
LF compresses and acts as fulcrum LUMBAR RF and LF slide upRF and
LF slide down RF slides down and LF slides up RF distracts and LF
compresses and acts as fulcrum Cervical Kinematics Notepack: page
26
Slide 12
OA Joint Complex Lateral Flexion I.A.R. White & Punjabi
(1990) 3-7 0 RIGHT Rectus Capitis Lateralis LEFT Occiput on Atlas R
Lateral Flexion Without Restraining Ligaments 5 0 Lateral OA
Flexion: White and Panjabi 1990 Lateral Flexion Restrained by Alar
Ligament
Loads on the Cervical Spine OA Joint: highest in full flexion
lowest in full extension Facing Forward, Slightly Retracted Correct
Posture Extended Flexed INCREASING LOADS LEAST GREATEST FOR JOINTS
C7-T2
Slide 15
DENS Flexion IVF increases in size Anterior Longitudinal Lig.
relaxed Posterior Longitudinal Lig. and Lig Flavum stretched
Ligamentum nuchae stretched Spinous Processes separate Nucleus
Propulsus pulled/pushed backward Anterior Annulus compressed
Posterior Annulus tensed Articular Facets unloaded, capsules
stretched C2 SLIDE EXTENSION SLIDE C3 SLIDE C7 SLIDE Extension IVF
decreases in size Anterior Longitudinal Lig. stretched Posterior
Longitudinal Lig. and Lig Flavum relaxed Ligamentum nuchae relaxed
Spinous Processes brought together Nucleus Propulsus pulled/pushed
forward Anterior Annulus tensed Posterior Annulus compressed
Articular Facets compressed, capsules relax
Slide 16
Osteokinematics of the Thoracic Spine
Slide 17
Extension IVF decreases in size AL Lig. stretched PL Lig. and
Lig Flavum relaxed Supra and Interspinous Ligs. relaxed Spinous
Processes Impact Nucleus Propulsus pulled/pushed forward Anterior
Annulus tensed Posterior Annulus compressed Articular Facets
Impact, capsules relax Flexion IVF increases in size AL Lig.
relaxed PL Lig. and Lig Flavum tensed Interspinous Ligament
stretched Spinous Processes separate Nucleus Propulsus
pulled/pushed backward Anterior Annulus compressed Posterior
Annulus tensed Articular Facets unloaded, capsules stretched
FLEXION EXTENSION T6 T7 T6
Slide 18
The Mechanics of Lumbar Rotation Segmental Rotation Minimal
segmental rotation !!! Contralateral facet impacts Ipsilateral
facet gaps + capsular stretch. Nucleus Pulposus is compressed Shear
stress on annulus Left Axis
Slide 19
Lumbar Lateral Flexion*** Segmental Lateral Flexion Ipsilateral
Vertebral Tilting Ipsilateral Annulus Compression Contralateral
Annulus Tension Nucleus pulled/pushed contralaterally Ipsilateral
IVF narrowing, contralateral enlargement Contralateral superior
facet: upward slide and decreased compression Ipsilateral superior
facet: downward slide and increased compression Contralateral
Transverse Lig tension, slack on ipsilateral COUPLING: ROTATION AND
IPSILATERAL SIDE BENDING ** IAR
Slide 20
TRUNK SIDE BENDING 1.Ipsilateral quadratus lumborum, erector
spinae and abdominal muscles initiate trunk side bending. 2.Gravity
then pulls the trunk further laterally (increasing the ipsilateral
side bending). 3.Erector spinae, Quadratus Lumborum, Gluteus Medius
on contralateral side contract eccentrically to control the rate
and the amount of gravity produced ipsilateral side bending.
4.Return to an erect posture is produced by concentric activity of
the Erector Spinae and Quadratus Lumborum on contralateral side.
Ipsilateral side
Slide 21
Arthrokinematics (Opening) STAGE 1 (EARLY PHASE) Notepack page
42 STAGE 2 (LATE PHASE) SLIDE TRANSLATION Condyle and Disc Move
Together Condyle Rotates Relative to Inferior Disc Surface
Slide 22
Arthrokinematics (Opening) EARLY PHASE During the initial 0 to
20 mm of opening (range: 11-25 mm) Condyles Rotate, (spin),
anteriorly on the disks. Disks stay in place Notepack page 42
Slide 23
Arthrokinematics (Opening) LATE PHASE: STAGE 2 During terminal
opening: (during the time when the jaw continues to open past the
initial 20 mm) Condyles and Discs together Translate Anteriorly
over the articular eminences with concurrent anterior rotation
Superior Lamina stretches, (which helps to control forward disc
displacement) Inferior Lamina tenses Jaw opening up to 40-50mm
Slide 24
Arthrokinematics (Closing) Initial Phase of Jaw Closing (
starts from the period of full opening, (~40-50mm), until
approximately 11-25mm of opening). 1. Condyles and Discs together
Translate Posteriorly over the articular eminences with concurrent
posterior rotation Superior Lamina recoils, (which helps to pull
the disc back posteriorly into the glenoid fossa). Inferior Lamina
relaxes Eccentric control of Lateral Pterygoid controls posterior
disk translation.
Slide 25
Arthrokinematics (Closing) Terminal Phase of Jaw Closing (
starts from the period of approximately 11-25mm of opening
(mandibular depression) until full closure-0 mm). 1. Condyles
rotate, (spin) posteriorly on the disks. 2. Superior and inferior
lamina are relaxed 3. Disk remains within the glenoid fossa.
Slide 26
Muscles Acting on the Mandible IL = ipsilateral CL =
contralateral
Slide 27
Trabecular or Cancellous bone Biomechanically an Internal
Scaffolding Network Notepack page 83-84 Support with Light Weight
Transmit Forces to Shafts
Slide 28
Cortical Bone The outer dense shell (5-10% porosity) Complex
network of cylindrical units of laminated bone (osteons) and
interstitial bone Osteons 2-3 mm long and about 0.2-0.3 mm in
diameter Run parallel to the long axis of a bone
Slide 29
Bending of Bone about an Axis Tensile forces/strains on the
convex side Compression forces/strains on the concave side
Slide 30
Bending of Bone about an Axis *** STRESSES ARE HIGHER AT THE
SURFACES OF THE BONE (cortical bone) AND LOWEST NEAR THE NEUTRAL
AXIS Neutral Axis of a Long Bone
Slide 31
Why? Because bone structure is dissimilar longitudinally vs.
transversely. BONE IS STRONGEST AGAINST COMPRESSIVE FORCES/LOADS
AND WEAKEST AGAINST SHEAR FORCES/LOADS OVERALL: From Nordin &
Frankel. 2001
Slide 32
Keys to Biomechanical Behavior of Bone Behavior is affected by:
1.Intrinsic mechanical properties (compact vs spongy) Flexibility
& resilience from its collagen (tensile strength) Rigidity
& strength from its minerals & water 2.Loading mode (GRFs,
muscle contraction) 3.Geometry (size, shape, and x-sectional area)
4.Direction of loading (anisotrophic characteristics) 5.Rate of
loading 6.Frequency of loading Note: There is a biomechanical
distinction between the mechanical behavior of bone tissue as a
material and the mechanical behavior of a whole bone as a
structure
Slide 33
General General Mechanics of Long Bones 1.Long Bones with
smaller diameters, (x-sectional areas), resist tensile stresses
better than thicker diameter bones. 1.X-sectional: longitudinal
ratios (wall to lumen ratios) 2.Differences in collagen alignment
2.Bones with larger diameters, (x-sectional areas), resist
compressive forces much better than bones with thin diameters.
3.Thin bones deform during bending, tension, and torsion with
greater magnitudes over thick bones. 4.Both spongy and compact bone
are weaker with tensile forces compared to compressive forces.
Slide 34
General Mechanics of Long Bones 5. Total bending is a function
of the length of a bone, (longer bones have a greater magnitudes of
bend vs. smaller). 6.Total strength of long bones during bending is
a function of x- sectional area, (thicker bones are stronger >
thinner bones). (Consider both compression and tension forces with
bending ) 7.Overall 7.Overall: compact bone is stronger in
compression, tension, and shear than spongy bone.
Slide 35
Mechanical Properties of Bone Compression/Tension Compact Bone:
1.Stiffer, (HIGHER Youngs Modulus), vs. cancellous 2.Stronger vs.
cancellous 3.Resists compression > tension (> shear) Notepack
page 93 Spongy Bone Bone tissue as a material.
Slide 36
Mechanical Properties of Bone Compression/Tension Cancellous
Bone: Less stiff, (LOWER Youngs Modulus), vs. cortical Weaker vs.
cortical Resists compression > tension Notepack page 93 Bone
tissue as a material.
Slide 37
Long Bones Mechanical Response to Tensile Forces (forces
directed away from a bones surface) Tensile Strength, (amount of
stress at failure) Greater in thin long bones > thick long bones
Tensile Strain (amount of strain at failure) Greater in thin long
bones > thick long bones Notepack page 94
Slide 38
Long Bones Mechanical Response to Compressive Forces (equal and
opposite forces directed towards a bones surface) Compressive
Strength, (amount of stress at failure) Greater in thick long bones
> thin long bones > Compressive Strain (amount of strain at
failure) Greater in thin long bones > thick long bones Notepack
page 95
Slide 39
Long Bones Mechanical Response to Bending Forces (forces
directed at bending a bone about an axiscombo of tension and
compression) Bending Strength, (amount of stress at failure)
Greater in thick long bones > thin long bones > Bending
Strain (amount of strain (bend) until failure) Greater in thin long
bones > thick long bones Notepack page 96
Slide 40
Long Bones Mechanical Response to Torsion Forces (forces that
cause a torque within the bone) Torsion Strength, (amount of stress
at failure) Greater in thick long bones > thin long bones >
Torsion Strain (amount of strain at failure) Greater in thin long
bones > thick long bones Notepack page 97
Slide 41
Fractures / Failures of Long Bones Site of a fracture is
dependent on: Type of forces applied. The distribution of spongy
and compact bone in the areas where forces are applied. Example:
epiphyses and tuberosities are prone to compressive fractures >
shafts of long bones Due to increased amounts of spongy bone and
decreased amounts of compact bone!
Slide 42
Fatigue of Bone Under Repetitive Loading Factors Leading to
Fatigue Fractures, (microfractures) 1. Repetitive low loads
(cycles) 2. The number of load applications cycles per unit of
time. 3. Muscle fatigue (inability to absorb some of the
energy)
Slide 43
Bone Fracture Healing Unorganized calcified osteoid secreted by
Osteoblasts Osteoblasts Osteoclasts 6 weeks 18-24 weeks Extremely
weak, unable to resist bending or torsion forces Macrophages
Slide 44
BONE IS ADAPTABLE AND MODIFIABLE!!!! Bone formed on Soft Tissue
Bone resorbed/formed at the same site Bone formed on existing
bone
Slide 45 thoracic >cervical) Compressi">
Vertebral Bones COMPACT BONE SHELL CANCELLOUS BONE CORE
COMPRESSIVE FORCES Strength related to vertebral size, (lumbar >
thoracic >cervical) Compressive loads shared by Cortical Shell
< Trabecular Core
Slide 50
Compressive Loading Strength Breaking Strength: Lumbar >
Thoracic > Cervical Adapted from White and Punjabi 1990
Slide 51
Vertebral Compressive/Tensile Strength and Aging 1.With age:
tensile properties decrease 10-20% 2.With age: decreasing
compressive properties Breaking load decreases 50% Strength
decreases 45% Strain decreases 40% 1. Gadek, A et al 2001
Compressive strength is related to the trabecular structure 1
Slide 52
1. Straightening of Relaxed (Wavy) Fascicles 2. Nerve Gliding
In relation to interfacing tissues Example: median nerve ulnar
nerve Internally, (interfascicular) 3. Nerve elongation (this
occurs via the elastic properties of its collagenous connective
tissue) 4. Intraneural Blood Flow Changes Decreased Blood Flow >
8% elongation of a nerve Complete Arrest of Blood Flow at 15%
elongation of a nerve Peripheral Nerve Responses to Tensile
Forces
Slide 53
Blood Flow Responses to Compression within a Peripheral Nerve
Reduction in Venous Flow at 20 30 mm Hg Inhibition of Axonal
Transport 30 50 mm Hg Inhibition of Blood Flow 30 50 mm Hg Complete
Loss of intraneural blood flow 50 70 mm Hg
Slide 54
Compressing a PN Circumferentially Adapted from Nordin &
Franken 2001
Slide 55
The Edge Effect of Circumferential Compressive Forces EDGE OF
COMPRESSION
Slide 56
ARROWS DEPICT DIRECTION AND MAGNITUDE OF NERVE FIBER
DISPLACEMENT CIRCUMFERENTIAL PRESSURE ON A NERVE INITIALLY CAUSES
DISPLACEMENT/DAMAGE OF NERVE FIBERS TOWARDS THE PERIPHERY (EDGES)
OF THE COMPRESSION = damage
Slide 57
Compressing a PN Laterally Caused by: A force that squeezes a
nerve against underlying: 1. Bone 2. Dense CTs, fibro- osseous
tunnels. 3. An abnormal dense mass (tumor). Cross-sectional
deformation of the nerve from circular to elliptical Mechanical
damage to axon membranes directly under the lateral contact areas.
Increased hydrostatic pressure.
Slide 58
Key Points Regarding Compression of a P.N. Generally larger
fibers are usually affected first > thinner fibers Larger fibers
undergo a relatively greater amount of deformation > thinner
fibers at a given pressure Clinically we often see the signs of
larger fiber damage first (large fibers carry motor function and
proprioception while thin fibers are ones that tend to mediate
pain, temperature)
Slide 59
Sustained Sustained Neural Compression Increased Hydrostatic
Pressure Neural Ischemia (Arterial and Venous) Neural Edema Neural
Fibrosis Loss of Intraneural mobility Loss of Extraneural mobility
Direct Mechanical Damage Peri & Epineuriums
Slide 60
PROGNOSIS for Compressive Forces (Magnitude and Duration) Good
Prognosis: low magnitude of force for short durations. Fair
Prognosis: high magnitude of force but only for a short duration.
Fair Prognosis: low magnitude of force for a long duration Poor
Prognosis: high magnitude of force for a long duration
Slide 61
DISLOCATION OF THE NODES OF RANVIER STRUCTURAL ALTERATIONS IN
THE MYELIN SHEATH STRUCTURAL ALTERATIONS IN THE AXONS ORGANELLES
FOCAL SEGMENTAL DEMYELINATION FIBROTIC CHANGES IN THE NEUROMUSCULAR
JUNCTION Leads to CHRONIC Blunt INJURY
Slide 62
Nerve Regeneration Nerve Regeneration** Axon degenerates Myelin
breaks down Macrophages clean up **Each injured AXON Crush or Cut
Injury 1 millimeter a day of re-growth
Slide 63
Stress Strain Curve (example: Hypothetical ACL Ligament) TOE
REGION ELASTIC REGION COMPLETE FAILURE PERMANENT DEFORMATION
PHYSIOLOGIC RANGE PLASTIC REGION
Slide 64
Straightening of Collagen Fibers Scanning Electron Micrographs
of Collagen Fibers Knee Medial Collateral Ligament) Unloaded
(non-stretched) collagen fibers Loaded (stretched) collagen fibers
WHY WOULD LIGAMENTS & TENDONS BECOME STIFFER AS STRAIN
INCREASES?
Slide 65
Youngs Modulus (of Elasticity) (the slope of the LINEAR ELASTIC
ZONE Y/X --- a.k.a. stiffness) MaterialModulus of Elasticity
(N/mm2) Stainless Steel 200,000 Titanium Alloy 100,000 Polyethylene
1000 Cortical Bone 18,000 Trabecular Bone 90 Female ACL 1 199 Male
ACL 1 308 Patellar Tendon 2 ( 6 months post ACL repair) 135 (- 66%)
Yamada H 1970 Chandrashekar 2005 Burks RT 1990 POLYETHYLENE
TRABECULAR BONE x y
Slide 66
Viscosity Application of a continuous force to a fluid
body..the body will continually deform.and we call this flow The
resistance to flow/shear is called viscosity (HINT: Think of it as
the internal friction of a liquid)
Slide 67
Viscoelastic Materials A material that seems to have both fluid
and solid properties A viscoelastic material displays both viscous
and elastic characteristics when undergoing deformation (examples:
tendons and ligaments) SOLID FLUID V
Slide 68
Viscoelasticity (when stress-strain curves change as a function
of time) Definition: time-dependent material behavior where the
stress response of the material depends on both: the amount of
strain applied RATEthe strain RATE at which it was applied! Most
biological tissues are viscoelastic!
Slide 69
Ex: Ligaments and Tendons Functionally Behave Elastically and
with Viscous Properties Notepack page 46 Viscous FlowElastic
Deformation
Slide 70
Time Dependent Viscous Effects and Time Dependent Behaviors of
Tissues (via the reorganization of collagen and PGs) 1.Deformation
Creep Response The tendency of a solid material to slowly move or
deform permanently under the influence of stresses, (constant
load). 2.Deformation Stress Relaxation Response The tendency for a
material held at constant length to experience a decreased
magnitude of stress (tension) Notepack page 62
Slide 71
Creep a time dependent deformation Length Application of
Constant Load Notepack page 62 Record Length Constant Load Applied
Load Tendon or Ligament Time 0
Slide 72
Tensile Load Time Specimen Held at a Constant Length Load
Relaxation a time dependent deformation Record Tension Notepack
page 62 Deformation Constant Deformation Stress Relaxation 0 Tissue
Fixed at Constant Length
Energy Lost as Heat/Molecular Rearrangement (Elastic
Hysteresis) No Energy Loss Energy Loss Notepack page 46 different
Loading and unloading occur on different stress-strain paths
Elastic
Slide 75
Resilience vigorously The property of a tissue to absorb energy
when it is elastically deformed and then, upon unloading to have
this energy vigorously recovered. Example: a rubber band shows a
fairly high degree of resilience. R = W W W Notepack page 48
Clinical Application Clinical Application: Tendons have the ability
to release the energy from being stretched. W = work
Slide 76
Tissue Damping The property of a tissue to absorb energy and
the rate and amount of energy that is dissipated when the tissue is
elastically deformed. The energy is not recovered directly back to
the tissue Opposite of Resilience Viscoelastic materials have
properties of damping, they are slower to recover their original
shape or length vs. purely elastic materials Strain Memory Foam D =
1 Resilience 0 Stress
Slide 77
Strength of a Tissue Strength is the magnitude of the force
needed to break a material. Stress (N/m2) Magnitude of Stress at
the point of COMPLETE FAILURE Strain 0
Slide 78
Toughness of a Tissue Stress Strain TOUGHER STRONGER Rambo The
amount of energy per volume that a material can absorb before
rupturing/failing. Toughness measured by considering the total area
under the stress strain curve Which is Stronger, Which is
Tougher?????? 0 0
Slide 79
Fragility vs. Toughness Failure TOUGH FRAGILE Toughness is not
necessarily equal to strength How much energy a material will
absorb before it fails or fractures???
Slide 80
Brittle vs. Ductile How much a material will plastically deform
before it fails or fractures??? Not necessarily related to
strength! 0
Slide 81
The Effects of Aging on Tissue Mechanics (combined properties
in general) Yamada 1970
Slide 82
Hydrated proteins Proteoglycans GAGS, (the carbohydrate
portion) 1.Hyaluronan (synovial fluid, cartilage) 2.Chondrotin
Sulfate (cartilage, tendons, ligaments, nucleus propulsus)
3.Dermatan Sulfate (skin, bvs, tendons, fibrocartilage, ligaments)
4.Keratan Sulfate (bone, cartilage, nucleus propulsus, annulus
propulsus) Glycoproteins Interfibrillar Matrix ** of C.T. **
PROVIDES SOME OF THE VISCOELASTIC PROPERTIES IN LIGAMENTS AND
TENDONS
Slide 83
ACL TENSILE LOADING Joint Instability + Pain Anterior Drawer
Test Some pain Slight weakening But NO CLINICAL JOINT INSTABILITY,
No Permanent Deformation Strain (%) Complete Failure
Slide 84
Physiological Responses of Tendon and Ligament to Stress*
Increased tensile stress leads to: (via mechanical, chemical, or
electrical signals?) 1.Addition of collagen fibrils, (increased
metabolic production from fibroblasts)?? 2.Increases in covalent
bonding between collagen molecules. Clinical Application: Following
injury or post surgical repair, small amounts of tensile forces
stimulate fiber orientation and collagen production (potentially
increasing its strength)????
Slide 85
Physiological Response to Injury in a Ligament/Tendon Day 2-4:
Cellular Stage Clot forms (erythrocytes, inflam. cells) Macrophages
and fibroblasts invade the damaged area (remove debris and begin
synthesis of a new CT matrix) Fibroblasts produce type III collagen
Union is weak and fragile, ruptures with very low tensile stresses
(stretching) Notepack page 64 Application: Protection from tensile
forces
Slide 86
Physiological Response to Injury in a Ligament/Tendon Day 5-21:
Fibroplasic Stage Matrix and Cellular proliferation stage Scar is
very cellular, (macros, mast, fibroblasts) Continued increase in
collagen synthesis but now also degradation as collagen remodeling
just begins towards the end of this phase. Collagen fibrils
beginning to enlarge Notepack page 64 Using what you have
learned!!! How would you rehabilitate the LCL of the knee with
respect to AROM during this phase????????? Application: Ideal time
to begin low tensile ROM Low tensile stresses helpful
Slide 87
Physiological Response to Injury in a Ligament/Tendon Day
21-60: Consolidation Stage Remodeling of collagen fibrils
organization Gradual in # of fibroblasts and macrophages Union is
progressively stronger Collagen fibrils increasing in diameter and
more densely packed, fibroblasts slow collagen proliferation
Increasing cross links as tissue is now becoming more stable and
less responsive to treatment that aims to effect collagen
organization Notepack page 64 Application: Progressively increase
tensile forces via AROM/PROM Repetitive low tensile stresses remain
helpful
Slide 88
Physiological Response to Injury in a Ligament/Tendon Day
60-360: Maturation Stage Primary strength from type I collagen.
Tissue appears only slightly disorganized and hypercellular. Tissue
is stable and union is stable. Poor ability to modify tissue
therapeutically. Application of adequate stresses increases fibril
density and covalent collagen cross linking. Application: More
aggressive but progressive increase tensile forces via
AROM/PROM/Exercises **** IN THE EARLY PART OF THIS PHASE TISSUE IS
STILL NOT ABLE TO RESIST EXCESS TENSILE LOADS.
Slide 89
Collagen Production and Tensile Strength Notepack page 65 C o l
l a g e n R e o r g a n i z a t i o n INJURY
Slide 90
Physiological Responses of Tendon and Ligament to Stress*
Increased tensile stress leads to: (via mechanical, chemical, or
electrical signals?) 1.Addition of collagen fibrils, (increased
metabolic production from fibroblasts)?? 2.Increases in covalent
bonding between collagen molecules. Clinical Application: Following
injury or post surgical repair, small amounts of tensile forces
stimulate fiber orientation and collagen production (potentially
increasing its strength)????
Slide 91
Physiological Response to Injury in a Ligament/Tendon Day 5-21:
Fibroplasic Stage Matrix and Cellular proliferation stage Scar is
very cellular, (macros, mast, fibroblasts) Continued increase in
collagen synthesis but now also degradation as collagen remodeling
just begins towards the end of this phase. Collagen fibrils
beginning to enlarge Notepack page 64 Using what you have
learned!!! How would you rehabilitate the LCL of the knee with
respect to AROM during this phase????????? Application: Ideal time
to begin low tensile ROM Low tensile stresses helpful
Slide 92
Aggregating hydrophillic PGs interspersed in an interfibrillar
collagen matrix attract large volumes of H 2 0 into the cartilage
matrix (+ PGs stiffen from negative repulsive actions of GAGS)
Influx of H20 increases osmotic pressure and subsequently expands
the interfibrillar matrix Expansion is resisted by tensile strains
of the collagen matrix Ability of Cartilage to Resist Compressive
Deformation
Slide 93
CREEP time Displacement equilibrium FLUID PHASE of ARTICULAR
CARTILAGE Notepack: page 73 After a constant load is applied fluid
WATER AND NUTRIENTS are extruded out of the cartilage INITIAL
LOAD
Slide 94
1.Fluid exudes through pores within the outer cartilage layer
2. Collagen and PGs begin to reorganize, CAN BE QUITE A DRAG!!!
With time (4 to 16 hours) equilibrium occurs when compressive
stress within the matrix and external load are equal No further
fluid flow Continued Initial Viscoelastic Behavior (CREEP of
articular cartilage) Notepack page 73
Slide 95
Viscoelastic Behavior (Stress relaxation of articular
cartilage) B E C A D STRESS TIME B to E: Fluid, PGs, and Collagen
are reorganized Key: This evens out compressive stresses from top
to bottom Notepack page 74 A to B: High stresses due to forced
rapid efflux of fluid STRESS RELAXATION LOADING CARTILAGE THICKNESS
T =
Slide 96
: Lowers viscosity of snovial fluid : Lubricates
Slide 97
Strength: total disc mass: lumbar > thoracic > cervical
Strength: per unit of fibrocartilage: cervical = lumbar >
thoracic Torsional Intervertebral Discs Torsional Properties Aging:
decreases torsional strengths to less than 20% of younger.
Slide 98
Viscoelastic Properties of the IVD IVDs exhibit: (NP > AF)
secondary to PGs Creep Relaxation Clinical: 1. Creep occurs slower
in healthy vs. degenerated discs. a. Creates increased stress to
supporting tissues 2. Discs have only peripheral blood supply and
peripheral nerve supply
Slide 99
Regulation of Muscles Extensibility* (The Musculotendinous
Unit) (in)Parallel Elastic Components Epimysium, perimysium,
endomysium sarcolemma, Titin filaments (in)Series Elastic
Components Tendons Contractile Elements SE CE PE *** Quite variable
among skeletal muscles due to individual characteristics of PE, SE,
and CE Hills Model of Skeletal Muscle bone SE
Slide 100
The Mechanical Ability of a Muscle to Stretch/Elongate is
Dependent Upon 1.The amount, the architecture, and make up of its
associated CT 2.Its active components (those that create resting
tension
Slide 101
Skeletal Fiber Arrangement Muscle fibers can shorten up to 30
50% of their length. Muscles with short fibers and large
physiological cross-sectional area, (PCSA), are designed for force
production. Muscles with long fibers and small PCSA are designed
for producing larger tendon excursions and joint motions with high
velocity.
Slide 102
FIBER ALIGNMENT SUMMARY FUSIFORM/PARALLEL FIBERS RUN NEARLY
PARALLEL TO THE LONG AXIS OF MUSCLE (+) LONGER MUSCLE FIBERS =
GREATER TOTAL MUSCLE SHORTENING, (increased tendon excursion). (+)
PARALLEL ALIGNMENT TRANSLATES INTO DIRECT SHORTENING OF MUSCLE
APPLIED TO TENDON versus (-) SHAPE LIMITS # OF FIBERS PER UNIT AREA
PENNATE FIBERS RUN AT OBLIQUE ANGLES TO THE LONG AXIS OF MUSCLE (-)
SHORTER MUSCLE FIBERS = SMALLER TOTAL MUSCLE SHORTENING (+) MORE
MUSCLE FIBERS PER UNIT AREA = GREATER FORCE POTENTIAL but: (-)
OBLIQUE ALIGNMENT TRANSLATES IN LESS THAN DIRECT SHORTENING OF
MUSCLE AND THUS LESS TENDON EXCURSION.