Title: Kinesiology
1Kinesiology
2Spinal Column Structure
- Base of support.
- Link between upper and lower extremities.
- Protects spinal cord.
- Stability vs. mobility
- Example cervical vs. thoracic spine
35 Regions of Vertebral Column
- Cervical
- Thoracic
- Lumbar
- Sacral
- Cocygeal
- 33 bones and 23 disks
4Curvatures Viewed Laterally
- Prior to birth C-shaped.
- 4 distinct curves in an adult.
5Cervical Lordosis
Thoracic Kyphosis
Lumbar Lordosis
6Spinal Motion
- Spinal movement is the combination of
- Intervertebral joints
- Facet joints
7Intervertebral Joints
8Intervertebral 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
9Disc 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.
10Disc 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.
11Disc 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.
12Annulus 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.
13Annulus 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.
14Disc 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
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16Longitudinal Ligaments
Anterior longitudinal
Supraspinous
Posterior longitudinal
Ligamentum flavum (elastic)
PLL diverts herniation posteriolaterally
17Posterior 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.
18Facet Joint
- Articulation between the superior (concave) and
inferior (convex) facets. - Guide intervertebral motion through their
orientation in the transverse and frontal planes.
19Facet 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.
20Intervebral 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
21Spinal Stability
- The columns ability to react to multiple forces
placed on it. - Degeneration increases instability.
- Body reacts to restore through fibrosus and
osteophytic changes.
22Types of Segmental Loading
- Axial Compression
- Bending
- Torsion
- Shear
23Axial 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.
24Axial 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.
25Bending
- 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.
26Torsion
- 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.
27Shear
- 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.
28Mobility
- Amount and direct of motion in a segment is
determined by - Vertebral body/disc size.
- Facet orientation frontal vs. sagittal.
29Flexion
- 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
30Extension
- 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
31Lateral 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.
32Rotation
- 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.
33Regional 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.
34Cervical
- CO - occipital
- C1 - Atlas
- C2 - Axis
- C3-6 - general basic structure
35Cervical Region Function
- Mobility gt Stability.
- Upper cervical unit C0-2
- Lower Cervical unit
- C2-7
36C0-1
- 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.
37C1-2
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.
38C2-7
- 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.
39Thoracic Spine Function
- Articulation for the ribs
- Least mobility
- Increasing load bearing
- Lat flex flex/Ext
40Thoracic 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.
41Thoracic 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).
42Thoracic 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.
43Thoracic 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.
44Lumbar Spine
- Most load bearing structures in the skeletal
system - Sagittal plane motion
- Largest body/disc, lamina and pedicles short and
thick for load bearing.
45Lumbar 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)
46Spinal Musculature
- Mobility vs. Stability
- Slow twitch SO vs. fast twitch FOG
- Energy storage
- Consider the line-of-pull of all spinal muscles
47Spinal Muscles
48Common Theme
Small angle of insertion Therefore
Rotary component
Compressive component
49Common Theme
Small angle of insertion Therefore
Rotary component
Compressive component
When are active vs. passive exercised indicated?
When are they not?
50Hip Flexors Abdominals
51General Comment Regarding Function
- Contracture vs. contraction
52General Comment Regarding Function
- Contracture of hip flexors and effect on lumbar
spine
53General Comment Regarding Function
- Abdominals
- Pelvic stability/balance
- Guy-support system
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