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Kinesiology

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Creep will occur in the disc, will be larger with increased force and aging. ... Discs also resist but if creep occurs - the facet may undergo more loading. Mobility ... – PowerPoint PPT presentation

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Title: Kinesiology


1
Kinesiology
  • The Spine

2
Spinal Column Structure
  • Base of support.
  • Link between upper and lower extremities.
  • Protects spinal cord.
  • Stability vs. mobility
  • Example cervical vs. thoracic spine

3
5 Regions of Vertebral Column
  • Cervical
  • Thoracic
  • Lumbar
  • Sacral
  • Cocygeal
  • 33 bones and 23 disks

4
Curvatures Viewed Laterally
  • Prior to birth C-shaped.
  • 4 distinct curves in an adult.

5
Cervical Lordosis
Thoracic Kyphosis
Lumbar Lordosis
6
Spinal Motion
  • Spinal movement is the combination of
  • Intervertebral joints
  • Facet joints

7
Intervertebral Joints
8
Intervertebral Disc
  • Intervertebral disk make up 20-30 of the height
    of the column and thickness varies from 3mm in
    cervical region, 5mm in thoracic region to 9 mm
    in the lumbar region.
  • Ratio between the vertebral body height and the
    disk height will dictate the mobility between the
    vertebra
  • Highest ratio in cervical region allows for
    motion
  • Lowest ratio in thoracic region limits motion

9
Disc Structure
  • Nucleus Pulposus (NP) is located in the center
    except in lumbar lies slightly posterior.
  • Gelatinous mass rich in water binding PG
    (proteoglycan) AKA (glycoaminoglycos) GAG-protein
    molecule.
  • Chondrotin-4 sulfate in PG molecule gives the
    disc a fluid maintaining capacity (hydrophyllic)
    - decreases with age.
  • Hydration of the disc will also decrease with
    compressive loading - this loss of hydration
    decreases its mechanical function.

10
Disc Structure
  • 80-90 is H2O decreases with age.
  • Disc volume will reduce 20 daily (reversible)
    which causes a loss of 15-25 mm of height in the
    spinal column.
  • Acts as a hydrostatic unit allowing for uniform
    distribution of pressure throughout the disc.

11
Disc Structure
  • Compressive stresses on the disc translate into
    tensile stresses in the annulus fibrosis
  • This makes the disc stiffer which adds stability
    and support to the spine.
  • Bears weight and guides motion.
  • Avascular - nutrition diffusion through end-plate.

12
Annulus Fibrosis
  • Collagen arranged in sheets called lamellae
    (outer layers).
  • These lamellae are arranged in concentric rings
    -10-12 layers that lessen in number with age and
    thicken (fibrose).
  • Enclose the nucleus and oriented in opposite
    directions at an angle of 120 degrees (or 45-65
    degrees).
  • Controls the tensile loading from shear,
    accessory motions in the anterior compartment and
    disc forces which can be up to 5x the external
    compression force.

13
Annulus Fibrosis
  • Mostly avascular and lacking innervation but the
    outermost layers are probably innervated
    (sinovertebral nerve).
  • Thickest anteriorly.
  • Outermost 1/3 connects to vertebral body via
    Sharpies fibers.
  • Outer 2/3 connect to the end plate.

14
Disc Pathology - Herniation
  • Highest incidence at C5-6, C6-7, L4-5, and
  • L5-S1.
  • Disc herniation
  • Disc protrusion or bulge - contained
  • Annulus intact.
  • Localized usually lateral
  • Diffuse usually posterior
  • Prolapsed not contained
  • Annular fibers disrupted inner layers
  • Extrusion - migration through all layers

15
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16
Longitudinal Ligaments
Anterior longitudinal
Supraspinous
Posterior longitudinal
Ligamentum flavum (elastic)
PLL diverts herniation posteriolaterally
17
Posterior Structures (Elements) of Motion Segment
  • Pedicles and lamina form the neural arch.
  • Facet joints between the superior and inferior
    articulating surfaces.
  • Transverse and spinous processes.
  • Interspinous and supraspinous ligaments.
  • Ligamentum lavum.
  • Intervertebral foramina.

18
Facet Joint
  • Articulation between the superior (concave) and
    inferior (convex) facets.
  • Guide intervertebral motion through their
    orientation in the transverse and frontal planes.

19
Facet Joint Capsule
  • Limit motions.
  • Strongest in thoracolumbar and cervicothoracic
    regions where the curvatures change.
  • Resist flexion and undertake tensile loading in
    the superior portion with axial loading or
    extension.
  • Resists rotation in lumbar region.

20
Intervebral Foramina
  • Exit for nerve root.
  • The size is dictated by the disc heights and the
    pedicle shape.
  • Will lose space with osteophytic formation,
    hypertrophy of ligaments and loss of disc height
    with aging lateral stenosis.
  • Decreases by 20 with extension and increases 24
    with flexion

21
Spinal Stability
  • The columns ability to react to multiple forces
    placed on it.
  • Degeneration increases instability.
  • Body reacts to restore through fibrosus and
    osteophytic changes.

22
Types of Segmental Loading
  • Axial Compression
  • Bending
  • Torsion
  • Shear

23
Axial Compression
  • Caused by gravity, ground reaction forces, muscle
    contraction and ligaments reaction to tensile
    forces.
  • Intradiscal loads can range from 294N to 3332N
    depending upon position.
  • Most load in anterior segment, posterior can load
    from 0-30 depending upon segments position.
  • Compression at the disk causes tension at the
    annulus, changing the angle of the fibers and
    increasing the stability.

24
Axial Compression (contd)
  • Creep will occur in the disc, will be larger with
    increased force and aging.
  • 5-11 of H2O is lost through creep.
  • Creep is rapid 1.5-2mm in 10 min.
  • Plateaus at 90 minutes.

25
Bending
  • Combination of compression, shear and tensile
    forces on the segment from translation.
  • Bending into flexion will be resisted by
    posterior annulus, PLL and the facet capsule and
    anterior compressive forces on the anterior
    structures causing disc displacement.
  • For extension posterior compressive forces in
    anterior segment and there is a tensile load in
    facet capsule and ALL.

26
Torsion
  • Caused by axial rotation and coupled motions.
  • Stiffness may increase due to facet compression
    with certain motions i.e., flexion increases
    torsional stiffness at L3-4.
  • Annulus fibrosus resists, 1/2 fibers CW other 1/2
    CCW facets may help depending upon the
    orientation (resists in a tensile manner).
  • When combined with flexion the amount of force
    required for tissue failure is decreased.

27
Shear
  • Facet joint resists especially in the lumbar
    area.
  • Annulus will undergo some tensile forces
    depending upon direction and the fiber
    orientation or angle.
  • Discs also resist but if creep occurs - the facet
    may undergo more loading.

28
Mobility
  • Amount and direct of motion in a segment is
    determined by
  • Vertebral body/disc size.
  • Facet orientation frontal vs. sagittal.

29
Flexion
  • Superior vertebra will anterior tilt and forward
    gliding will occur
  • Widening the intervertebral foramina 24.
  • Adds compressive forces on the anterior aspect
    of the anterior segment moving the nucleus
    pulposus posteriorly.
  • Tensile forces placed on posterior annulus,
    flavum, capsule and PLL.
  • Central canal is widened
  • Rationale for some of Williams flexion exercises

30
Extension
  • Superior vertebra will tilt and glide posteriorly
    and the intervertebral foramina narrowed up to
    20.
  • The central canal is also narrowed.
  • Nucleus pulposus moves anteriorly

31
Lateral Flexion
  • Superior vertebra will translate, tilt and rotate
    over inferior - direction will differ.
  • Concavity towards, convexity opposite
  • Tensile forces on convexity, compressive forces
    on concavity
  • Extension in ipsilateral facet.
  • Flexion in contralateral facet.

32
Rotation
  • Accessory motions are like lateral flexion due to
    same coupling in cervical and upper thoracic
    spine.
  • Exception with lower T/S and L/S in neutral
    coupling then opposite (in most references).
  • If the motion segment is flexed or extended spine
    (in most references) the coupling will be the
    same.

33
Regional Structural andFunctional Differences
  • Differences are apparent due to connection
    requirements, sacral, upper C-spine, all
    junctions
  • Vertebral body size increases with support
    requirements.
  • Cervical, thoracic,lumbar, and sacral/cocygeal.

34
Cervical
  • CO - occipital
  • C1 - Atlas
  • C2 - Axis
  • C3-6 - general basic structure

35
Cervical Region Function
  • Mobility gt Stability.
  • Upper cervical unit C0-2
  • Lower Cervical unit
  • C2-7

36
C0-1
  • C0 occiput containing the occipital condyle
    convex.
  • C1 - no body, disk and spinous process allows for
    free space and a large neutral zone and cord
    protection - this means more motion.
  • Lateral facets of CO on C1 - concave C1 on convex
    CO - flex/ext or nodding and minimal to no
    lateral flexion/rotation.

37
C1-2
Dens
  • 2 facets laterally and 1 medially with dens and
    anterior arch
  • transverse ligament helps control (C1 on C2
    anterior displacement), stabilizes allows
    nodding
  • also provides cartilaginous surface as does the
    alar ligament - limits flex/ext so right rotation
    requires left lateral facet to slide anterior and
    right lateral facet to slide posterior so
    rotation is coupled with extension.
  • Can account for up to 50 of rotation in the neck
    and most of the initial ROM.

38
C2-7
  • 50 wider than they are deep.
  • Transverse process holds foramen for vertebral
    artery, vein and plexus, and grove for the spinal
    nerve.
  • Facet orientation is roughly 45 degrees(35-65) in
    the transverse plane w/ loose capsule - allows
    for motion in all planes and more rotation and
    lateral flexion than other regions.

39
Thoracic Spine Function
  • Articulation for the ribs
  • Least mobility
  • Increasing load bearing
  • Lat flex flex/Ext

40
Thoracic Spine Body
  • T1 - similar to cervical in (C7a).
  • Normally the vertebral body equals width and
    depth.
  • The ratio of disc diameter to height is highest.
    This will
  • Decrease tensile forces
  • Decrease possibility of disc injury
  • Posterior aspect becomes thicker as you go lower
    - ribs bigger (articulates) and more compressive
    forces.
  • End-plates become larger (higher compressive
    forces) as you go caudally.

41
Thoracic Spine
  • Less flexible due to rib articulation, smaller
    disc to body ratio, spinous process.
  • Flavum and ALL are thicker facet capsule less
    flexible.
  • Upper thoracic spine facet orientation
  • Limits flexion extension - 60/20 transv/front
  • Allows coupled lat/rot. (rot of spinous process
    to the convex side)
  • Facets are more sagittal in T9-12 to allow
    flex/ext and rot of spinous process will be
    toward concavity (lumbar coupling).

42
Thoracic Spine
  • Rib articulation consists of 2 articulations to
    the thoracic vertebra
  • Anterior surface of the lateral process
  • Lateral aspect of the vertebral body.
  • Bucket handle motion of the ribs with breathing.
  • Extension and contralateral lateral flexion ribs
    separate.
  • Flexion and lateral flexion ipsilaterally
    compresses ribs.

43
Thoracic Spine
  • Scoliosis will cause a rib hump.
  • Combination of tranverse plane rotation and
    frontal plane sidebend contralateral coupling.
  • Convex side will occur on the ipsilateral rotated
    side causing hump.

44
Lumbar Spine
  • Most load bearing structures in the skeletal
    system
  • Sagittal plane motion
  • Largest body/disc, lamina and pedicles short and
    thick for load bearing.

45
Lumbar Spine
  • L5 transitional, wedge shape of body and disc
    Anterior gt posterior.
  • L5-S1 most flexion extension.
  • Coupling of motion - right lateral flexion will
    result in right sidebend and left rotation of
    vertebral body (when L/S in neutral)

46
Spinal Musculature
  • Mobility vs. Stability
  • Slow twitch SO vs. fast twitch FOG
  • Energy storage
  • Consider the line-of-pull of all spinal muscles

47
Spinal Muscles
48
Common Theme
Small angle of insertion Therefore
Rotary component
Compressive component
49
Common Theme
Small angle of insertion Therefore
Rotary component
Compressive component
When are active vs. passive exercised indicated?
When are they not?
50
Hip Flexors Abdominals
51
General Comment Regarding Function
  • Contracture vs. contraction

52
General Comment Regarding Function
  • Contracture of hip flexors and effect on lumbar
    spine

53
General Comment Regarding Function
  • Abdominals
  • Pelvic stability/balance
  • Guy-support system

54
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