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101 Cards in this Set
- Front
- Back
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What are the functions of the annulus fibrosis?
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-contains nucleus
-stabilizes vertebrae -permits multidirectional mvmt -absorbs shock |
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How does the annulus fibrosis affect spine movement?
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-proteoglycans and collagen fibers limit deformation of the annulus stabilizing the spine while allowing mvmt
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What are the functions of the nucleus pulposus?
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-absorb/retain water
-force transmission -nutrition -equalizes unit stress to annulus -permits rocking of vertebral bodies |
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How does the nucleus pulposus affect spine movement?
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-spherical shape allows vertebral bodies to pivot in multiple directions
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What comprises the cruciform ligament?
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-transverse ligament of atlas
-superior band to occiput -inferior band to body of axis |
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What are the functions of the cruciform ligament?
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-"sling" which holds the dens in alignment, inferior and superior bands prevent slippage of the sling
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What are the consequences to a slack or torn cruciform ligament?
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-could lead to wobbly dens and uneven rotation decreasing rotation ROM and increasing joint wear
-could also allow dens to move posterior into spinal canal compressing SC |
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What is the function of the alar ligaments?
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-to limit rotation @ the O/A jt
-maintain dens placement -limit possible stretching of the cruciform ligament by the dens |
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What structures limit extension of the spine?
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-anterior longitudinal lig
-annulus fibrosis -facet joints -anterior musculature |
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What can occur as a result of anterior longitudinal ligament slack?
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anterior slippage of one vertebral body on another which:
-decreases the intervertebral foramen increasing nerve root compression -increases facet compression decreasing mvmt in all planes |
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What structures limit flexion of the spine?
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-supraspinous lig
-interspinous lig -ligamentum flava -posterior longitudinal lig -annulus fibrosis -posterior musculature |
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What is the function of ligamentum flava?
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-limit flexion
-prevent capsule pinching -recoil repositions facet jts -control rate of facet motion during flexion |
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Slack of the ligamentum flava can cause what dysfunctions?
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-abnormal segmental mvmt
-pinching of the capsule -bulging into the spinal canal compressing SC (known to occur in cspine during extension) |
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How does the rib cage affect movement of the spine?
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-limits movement in all directions of the t-spine
-lower ribs can limit l-spine sidebending |
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What are the ligaments stabilizing the spine?
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-anterior longitudinal
-posterior longitudinal (tectorial membrane) -interspinous (C7-L5/S1) -supraspinous (C7-L4) -ligamentum flava -ligamentum nuchae (C7-occiput) -intertransverse |
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What facet motions occur with flexion of the spine?
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-bilateral upslide in lower c-spine, t-spine, and l-spine
-lower c-spine also slides forward |
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What facet motions occur with extension of the spine?
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-bilateral downslide in all regions
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What facet motions comprise sidebending of the spine?
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-facets on the side toward the motion slide down
-facets opposite the side of motion slide up -lower c-spine also has accompanying forward and backward sliding |
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What arthrokinematic motions occur in the lumbar and thoracic spine during rotation?
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-facet towards the direction of rotation gaps
-facet opposite the rotation compresses and acts as a fulcrum |
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What arthrokinematic motions occur at the O/A joint during rotation?
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-condyle towards rotation moves slightly back
-condyle opposite rotation moves slightly foward |
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What arthrokinematic motions occur at the A/A joint during rotation?
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-facet towards the rotation moves back
-facet opposite the rotation moves forward |
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How does spine rotation affect the components of the spinal segment?
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-nucleus compression increases
-annulus sheared -facet opposite rotation compressed -facet toward rotation gapped -joint capsule toward rotation stretched |
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What direction does the SI joint move in primarily and how far does it move?
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-anteroposterior
-approx 1-3 degrees (F>M avg) -rotation and translation occur |
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What is nutation of the SI joint?
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-sacral movement in relation to the ilium as occurs in squatting and forward bending of the trunk
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What is torsion of the SI joint?
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-movement of the ilium in relation to the sacrum as occurs in supine DKC
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When are the loads at the A/O joint lowest?
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-full extension
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When are the loads at C7-T1 the least? The greatest?
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-head directly foward with the chin tucked < head extended < head fully flexed
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What muscular actions produce forward flexion of the spine?
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-abs and iliopsoas initiate flexion
-gravity takes over -erector spinae eccentrically control flexion until 60 deg -at 60 deg, ant pelvic rotation occurs controlled by glut max and hamstrings |
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What muscular actions produce extension of the spine from a foward bent position?
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-erector spinae stabilize spine in full flexion
-glut max and hamstrings post rotate the pelvis 30 deg -erector spinae concentrically complete extension for last 60 deg |
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What muscular actions produce sidebending of the spine?
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-QL, erector spinae and abs on same side initiate SB, then gravity takes over
-QL, erector spinae and abs on opposite side control SB eccentrically |
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Which muscles extend, sidebend and rotate the vertebrae to the same side?
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-splenius cervicis
-iliocostalis -longissimus |
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Which muscles extend and rotate to the opposite side?
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-semispinalis cervicis
-multifidi -trapezius |
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What active and passive forces resist the line of gravity in the cervical spine?
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passive = anterior longitudinal lig
active = none EXT moment |
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What active and passive forces resist the line of gravity in the thoracic spine?
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passive = post longitudinal lig, lig flavum, supraspinous lig,
active = back extensors FL moment |
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What active and passive forces resist the line of gravity in the lumbar spine?
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passive = anterior longitudinal lig
active = none EXT moment |
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What active and passive forces resist the line of gravity at the A/O joint?
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passive = lig nuchae, tectorial membrane
active = posterior neck muscles FL moment |
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What active and passive forces resist the line of gravity at the SI joint?
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passive = sacrospinous lig, sacrotuberous lig, sacroiliac lig
FL moment |
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What occurs at the TMJ during stage 1 of jaw opening?
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-ant rotation of mandibular condyle in fossa/on disk
-disc stays in place -sup and inf lamina relaxed -11 to 25mm b/n incisors |
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What occurs at the TMJ during stage 2 of jaw opening?
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-ant rotation and translation of mandibular condyle over articular eminence
-disc translates anteriorly -sup lamina stretch, inf lamina tightens -40 to 50 mm b/n incisors |
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What occurs during stage 1 of jaw closing at the TMJ?
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-post rotation and translation of the condyle back into fossa
-post translation of disc -sup lamina recoils pulling disc -inf lamina slackens -lat pterygoid controls the rate of disc mvmt posteriorly |
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What occurs during stage 2 of jaw closing at the TMJ?
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-post rotation of the condyle in the fossa and on the disc
-disc in fossa -sup and inf lamina relaxed |
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What's the difference between the elastic and plastic regions of a stress/strain curve?
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-elastic tissue or region will return to its original position after load is removed
-forces that strain a tissue into its plastic region cause a permanent deformation |
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What is Young's Modulus?
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- E = stress/strain
-high Young's modulus indicates high force (stress) with little strain -low Young's modulus shows high strain (deformation) with little stress |
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What does Young's Modulus indicate about the elasticity of a tissue?
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-HIGH Young's is little deformation with high forces, meaning the tissue is STIFF
-LOW Young's is lots of deformation with low forces indicating the tissue is ELASTIC |
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What is Resilience of a tissue?
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- R = (W - changeW)/W
-it is the mechanical work lost during deformation indicated by the area between the stress/strain curves |
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What is Damping?
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-the opposite of resilience
- D = 1 - R - good damping materials are not elastic |
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What is Toughness?
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- resistance to mechanical failure (amt of energy absorbed by a material before it breaks)
- energy absorbed is the area under the stress/strain curve -strength and toughness are NOT equal |
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What is Fragility?
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-opposite of toughness
-material absorbs very little energy before it fails |
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What is Brittleness?
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-very little strain occurs before failure
-materials can be strong and brittle or weak and brittle |
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What is tissue strength?
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-the amount of stress required to cause tissue failure
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What is Ductility?
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-progressive deformation in tension without failure
-old bone vs young bone: young bone more ductile b/c it deforms farther with tension than old bone |
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Where is Type I Collagen found and what are it's functions?
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-found in: skin, bone, tendon, ligament, fibrocartilage and fascia
-resists tension and stretching |
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Where is Type II Collagen found and what are it's functions?
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-found in: hyaline cartilage and elastic cartilage
-resists pressure |
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Where is Type III Collagen found and what are it's functions?
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-found in: connective tissue of organs, BVs, nerves and muscles
-support structure and important for WOUND closure |
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What are the functional benefits of Loose CT, Dense Irregular CT, and Dense Regular CT?
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LOOSE = permits MOVEMENT
DENSE IRREG = MULTIDIRECTIONAL tension resistance and shear force, protection DENSE REG = transmits UNIDIRECTIONAL tension force |
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How do Glycoaminoglycans aid in resisting forces?
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-with compression negatively charged GAGs are approximated and repel eachother
-tension forces result in tissue compression so GAGs also help collagen resist tension |
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Differentiate between the toe, elastic, and progressive failure regions of the Tendon/Lig stress strain curve.
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TOE = SLACK out of collagen
ELASTIC = collagen TIGHTENS, 1:1 stress/strain ratio PROG FAILURE = fibers BREAK, small stress = large strain |
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How does rate of applied tension affect the tendon/ligament response?
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SLOW RATE: low stress = high degree of deformation
HIGH RATE: high stress = much less elongation |
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What are the functional implications of applying high and low rate stresses to tendons/ligaments?
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LOW RATE = good for stretching, would not allow optimal muscle action and mvmt
HIGH RATE = rapid mvmt required, so less mvmt of the tendon results in faster mvmt of the segment |
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How do tendons/ligaments respond to tension?
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tension STIMULATES COLLAGEN production and CROSSLINK FORMATION, which strengthens tendon/ligament
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How does the stress/strain curve relate to tendon/ligament injury?
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-inc tension = inc microfailure
-inc microfailure to yield pt = permanent deformation and INSTABILITY -pain and inflammation occur with microfailure |
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What's the difference between Creep and Load Relaxation?
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CREEP = inc strain with constant load
LOAD RELAXATION = dec stress with constant strain (no change in tissue length) |
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What property allows Creep and Load Relaxation?
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-GAGs and collagen reorganize in the tissue over time, allowing either inc strain or dec stress
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How does tension benefit the repair of tendons/ligaments?
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-collagen production
-large collagen bundle production -controls fiber alignment -inc scar strength -inc rate of healing and completeness of healing |
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When is the most effective time to apply tension during the process of tendon/ligament repair?
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-Fibroplasia stage (5-21 days) and early Consolidation (just after 21 days) when collagen is being produced and remodelled
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How does ligament replacement differ from tendon/ligament repair?
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-application of tension to the structure must be delayed due to initial degradation of the structure over several weeks
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How does immobilization affect joint and surrounding tissues?
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-loss of strength and stiffness
-NO INFLAMM = 7 weeks no effect on ligs/capsule -INFLAMM = adhesions w/in 4 weeks |
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What are the effects of aging on the mechanical properties of tendons/ligaments?
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- 70> = only 5-10% dec
- >70 = 20% dec in tensile strength (weaken), 10% dec in elongation (shorten) -affect ligs>tendons |
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How are tension and compression resisted in articular cartilage?
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COMPRESSION = GAGs
TENSION = TYPE II COLLAGEN FIBER (also resists shear) |
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What are the functions of proteoglycans in articular cartilage?
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-resist compression
-aid nutrition |
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How does cartilage receive its nutrition?
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-avascular, so depends on compression-relaxation
-compression removes H2O and waste, relaxation and GAGs bring H2O and nutrients back in -complete ROM required to feed ALL chondrocytes |
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Why does the articular cartilage tension stress/strain curve lack a plastic region and what does this imply about its failure in comparison to tendons/ligs?
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-less dense and smaller type II collagen compared to type I of tendon/lig
-more proteoglycans and H2O => failure without yield point and plastic region |
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How does creep occur in articular cartilage?
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-CONSTANT LOAD compresses H2O and waste out, collagen and GAGs reorganize and further decrease the thickness of the cartilage
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How does stress relaxation occur in articular cartilage?
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-the thickness of the cartilage remains constant with stress focused superficially
-over time, collagen and GAGs realign to even the stress throughout the cartilage |
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What are the 3 types of Synovial Joint lubrication?
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-BOUNDARY: last ditch, lubricant forced out of surface layer
-HYDRODYNAMIC: jt surfaces not parallel, fluid drawn b/n with mvmt -SQUEEZE FILM: parallel, fluid squeezed out of concavity w/ compression |
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What are the types of articular cartilage wear?
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INTERFACIAL:
-adhesive: sticky surfaces, mvmt tears surface -abrasive: particles pressed into surface w/ mvmt FATIGUE: age/sport IMPACT: very high rapid forces |
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What are the steps of articular cartilage degeneration?
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-fibrillation
-cavitation -vertical splitting -continued erosion |
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What are the effects of aging on articular and fibrocartilage?
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ARTICULAR - by 40, noticeable dec in tension/compression, greater after 50
FIBROCARTILAGE - tension/torsion dec slight by 40, continue after 40 |
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What resists tension and compression in bone?
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tension - type I collagen and ground substance of the matrix in herringbone patter
compression - inorganic salts |
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What are the reasons for remodeling bone throughout the life span?
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-microfx repair
-replenish osteocytes -adapt to stresses -make Ca2+ available to body -bony callus remodelling during fx healing |
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How does bone remodeling occur during growth?
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-cylindrical: osteoblasts deposit in subperiosteal, osteoclasts reabsorb in subendosteal
-conical: osteoblasts deposit in subendosteal, osteoclasts reabsorb subperiosteal |
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How does internal bone remodeling occur?
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-old lamellar bone removed in cavity called cutting cone
-cutting cone contains BVs and CT, and cells giving rise to osteoblasts -becomes closing cone as osteoblasts lay down bone on cone wall |
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What are the differences in spongy and compact bone and how do they effect bone strength?
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-SPONGY is NETWORK of spiny processes at the ends of long bones, WEAKER
-COMPACT is SOLID with osteon columns in shafts of long bones, STRONGER |
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How does a large cross sectional area of bone affect its mechanical properties?
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-more resistant to compression, bending, and torsion
-weaker in tension b/c of hollow structure -deform less than spongy bone |
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How does a small cross sectional area of bone affect its mechanical properties?
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-weaker in compression, bending and torsion, stronger in tension than bones with larger xsection area
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How does aging affect the general properties of bone?
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-max strength 20-29yo, gradual decrease after 30
-after 50, trabecular bone strength and amt decrease more rapidly in females |
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How does aging affect long bones?
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-TENSILE and BENDING decrease 25% after 50 yo
-COMPRESSION and TORSION decrease only 15% after 50 |
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How does aging affect vertebral bodies?
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-tensile forces of bodies dec 20%
-compression resistance dec 40-50% -torsion resistance dec 40% |
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What comprises each of the regions of the myofilament: A-band, H-zone, M-ling, I-band, and Z disc?
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A-band: actin and myosin overlap, crossbridges formed
H-zone: myosin only M-line: myosin filaments overlap I-band: contain only actin Z disc: actin overlaps |
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What adaptations can occur within a muscle cell in response to condition changes?
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atrophy - loss of myofibril
hypertrophy - gain of myofibril length inc - increase # of sarcomeres at ends of muscle |
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How does muscle fiber arrangement affect force production and displacement?
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Parallel: all of force is in line with tendon, fiber contraction equals tendon displacement
Pennate: some force is not directed in line with pull and direction results in less tendon displacement; MORE Muscle fibers = inc total force |
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What are the three elements of Maxwell's model?
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1) A&M the contractile unit
2) series elastic component is tendon 3) parallel elastic component is the CT of the muscle |
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How does Maxwell's model explain the events of muscle contraction?
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1)A&M first tighten the series and parallel elastics
2)movement then begins 3)passive prestretch causes initial contraction to result in movement 4)elastic components return muscle to resting length |
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According to the Muscle Tension-Elongation curve, which muscles are difficult to stretch and which are easier?
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Difficult: sartorius, SCOM
Easier: pec major, gastroc, rec fem |
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What explains the difference in stretchability between different muscles?
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-resistance to elongation produces muscle tension
-rapid rise in tension (SCOM, sartorius) = hard to stretch -gradual increase in tension (pec major, gastroc) = easier to stretch |
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How does the temperature of muscle affect its function?
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-increased temperature allows inc enzyme activity and crossbridge formation = MORE FORCE
-does not affect ability to stretch muscle |
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How does aging affect muscles?
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-muscles grow to peak size and strength in 20s
-after 30-40 yo decrease in: fiber number, isometric strength and contraction velocity |
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How can nerve fibers in a peripheral nerve be damaged when tension is applied?
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-physical damage from the compression, tensile and shear stress/strain
-inc hydrostatic pressure -BV may become stretched, dec blood flow to nerve |
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How can nerve fibers be damaged by compression?
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-circumferential = surface dmg, like a BP cuff
-lateral = "edge effect" area under compression is damaged like a sandwich |
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Why is nerve regeneration so unsuccessful in a mixed nerve?
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-schwann cell availability to form tunnels (all nerves)
-motor and sensory nerves have difficulty finding like nerves |
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How do you determine the prognosis of a nerve injury?
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low force + short duration = good
high force + short duration = fair low force + long duration = fair high force + long duration = poor |
