2 - Lumbar Spine Review and Current Concept

intervertebral disc (IVD) shape

BEAN

IVD in youth

more fluid

IVD with increased age

more fibrous

what part of IVD is most vulnerable to degeneration?

posterior lateral area bc it is the furthest away from axis

nerve roots

differentiate and travel caudally across superior structures before exiting

What must you use to differentiate what nerve roots are affected?

neuroscreen and segmental/translatory motion assessment

- cannot diff. level of problem just by neuro signs bc nerve roots cross multiple segments

- do segmental shearing test and correlate w MRI imiging

Facet joints attenuate

significant anterior shear forces - born on anteromedial region of superior facet, near foraminal space

what ligament makes up the anterior facet joint capsule?

ligamentum flavum

What can happen to the ligamentum flavum with aging and degenerative changes?

can hypertrophy (less elastic, thickens)

- encroaches on intervertebral foramina --> nerve impingement

- bunches up as facet joints close

what ligament makes up the posterior facet joint capsule?

multifidus

intra-articular meniscoids

present in capsule

meniscoids

- fatty deposits

Intraarticular synovial fold inclusions which can become entrapped between the superior and inferior articular processes, producing the acute "locked back syndrome"

Posterior Longitudinal Ligament (PLL)

may play a role in preventing (central) disc protrusion

Ligamentum flavum prevents

facet joint capsular entrapment

Hypertrophy of Ligamentum Flavum can contribute to what pathology?

degenerative stenosis

Iliolumbar ligament restrains

all motionsc at L5-S1

Thoracolumbar Fascia envelopes

lumbar musculature

what tensions the TLF?

hypertrophy of muscles

TL fascia attachments

- spine, other ligaments

- latissumus dorsi

- transverse abdominus

what is the major arthrokinematic controller? what is it responsible for?

multifidus

- responsible for 2/3 of lumbar spine stiffness

when are the multifidi active?

ALL antigravity activities

what commonly occurs with the multifidi in patients wit LBP

reduced in size = ATROPHY

- reduction persists after pain has resolved

- may be restored with specific strengthening

- ALWAYS ADDRESS multifidus in LBP

Innervation of lumbar spine muscles

segmentally

the lumbar muscles being segmentally innervated means that they can be segmentally

impaired

- some may spasm, some may not

Lumbar spine muscles always work during what movement?

rotation

transverse abdominus plays a vital role in stability by

creating a rigid cylinder and enhancing lumbar stiffness via attachments to thoracolumbar fascia

~ reciprocally facilitates w intrinsic and extrinsic to maintain columnar integrity of spine and cylinder (PF and diaphragm)

iliopsoas attachments

- bodies

- disks

- TVPs of lumbar spine

iliopsoas can create

compression

- can increase lordosis and anterior shear

- acts as stabilizer

Predominant motion available at lumbar spine

flexion

- most commonly used in everyday activities

full flexion usually results in what?

flattening of lordosis w slight reversal lordosis in some cases

Kinematics of vertebral body during flexion

rocks anteriorly (slight anterior glide)

Kinematics of inferior facets of superior vertebrae during flexion

glide predominantly superiorly and slightly anteriorly

facet joint contact in full flexion is

minimal

- prone to injury

Flexion - kinematics of the disc

anterior disc compressed, posterior disc is tensioned

What prevents excessive anterior translation?

facets and capsule, multifidus and erector spinae, ligaments and disc

Flexion kinematics: intervertebral foraminal space and spinal canal space

intervertebral foraminal space and spinal canal space is increased

what is the primary limiter during flexion? (anterior shear)

DISC!! and facets

Kinematics - extension

reverse of flexion

- body rocks posteriorly

- facets glide inferiorly

- posterior disc compressed

- anterior disc tensioned

Extension Kinematics: space

intervertebral foraminal space is reduced

- space in spinal canal is reduced

Extension kinematics: ligamentum flavum

bunched if degenerated

Extension kinematics: facet joints

closed packed

Extension kinematics: limited by

bony contact and ability of disk to allow tension anteriorly and compression posteriorly

Extension Kinematics - facet joints

glide inferiorly -> posterior disc compressed

- mostly as a return from flexion to neutral

Sidebending Kinematics - with flexion kinematics

SB occurs w flexion kinematics on contralateral side

Sidebending Kinematics - with extension kinematics

SB occurs w extension kinematics on ipsilateral side

Coupled motions of rotation to the ____ side may occur

opposite side

Rotation kinematics

- compresses contralateral facet

- decompresses ipsilateral facet

Rotation kinematics: foraminal space

intervertebral foraminal space is unchanged

Right rotation opens

RIGHT

- R rotation moves spinous process left

What % of fibers in disk are tensioned with rotation?

50%

what range of rotation at each segment in neutral flex/ext does not allow sufficient motion to injure the disc?

3° to 5° of rotation

what motion coupled with rotation allows increased rotation and may injure a disk?

flexion

~ Allows increased rotational torsion on disc = more vulnerable to injur

what structure limits rotation? (in the case of trauma may injure facet joint as well)

facet joint and exressive rotation

Compression/axial loading of lumbar spine is associated with

associated with disc height

with compression/axial loading, water is squeezed out of disc RAPIDLY in what time?

rapidly in the first 2-10 minutes

- THEN slowly after

what percent of disc height is lost throughout the day?

10%

how is disc height restored?

with unloading

Excessive compression may result in loss of...

disc height and degenerative changes

- degeneration = negative effects amplified

Compression - forces are transferred to the facet joints...

abnormal loading causes facet joint hypertrophy. loss of intervertebral foraminal space

distraction rarely occurs in everyday life in a ____ fashion

symmetrical

what primarily limits distraction?

annulus fibrosis

what does distraction allow?

imbibtion of fluids by the disc

how is distraction most often done?

most often employed therapeutically

- Can perform some SB before they get up bc you can imbibe too much and squish into foraminal space

Neutral Zone

region of laxity around neutral resting position of the spine.

Neutral Zone: stability depends on...

- active system

- passive system

- CNS system

Role of active system is...

essential throughout ROM for Stability to occur

Active system

trunk muscles - mobilizers and stabilizers

active system: mobilizers

move trunk thorugh space

active system: stabilizers

maintain general trunk stiffness

active system: stabilizers are classified as

- global stabilizers

- local stabilizers

global stabilizers (4)

- Rectus abdominis

- Internal/external oblique's

- Lateral fibers of QL

- Thoracic part of lumbar illiocostalis

do lumbar global stabilizers have segmental influence?

NO

- but increase general trunk stiffness

- eccentrically decelerate momentum and control gross rotation of trunk

local stabilizers (5)

- Lumbar multifidus

- Transverse abdominus (attaches to TFL)

- Posterior fibers of Internal oblique

- Medial fibers of QL

- Lumbar portions of illiocostalis and longissimus thoracis