Lecture 2A: Lumbar Spine Anatomy

Question 1

Axial Rotation

horizontal articular surfaces
vertical articular surfaces

clarifier

footnote

Answer 1

horizontal structres favor axial rotation
vertical blocks axial rotation (i.e. lumbar spine)
note: facets of the lumba are oriented vertically in the sagittal plane

Question 2

spinal motion amount of available motion is affected by?

Answer 2

• disc vertebral height ratio
• compliance of fibrocartilage
• dimention / shape of adj vertebral end plate
• age
• disease
• gender

Question 3

type of motion available govered by

Answer 3

shape and orientation of the articulation
ligaments / mm
size and location fo the articulation

Question 4

most available motion is in the____spine bc it has largest facets

Answer 4

Lumbar

Question 5

what’s the largest avascular structure in the body?

Answer 5

IVD

Question 6

5 major stresses that the IVD Can resist are:

Answer 6

1. axial compression
2. shearing
3. bending
4. twisting
5. combinted motion

Question 7

T/F IVD does not resist tension

Answer 7

T

Question 8

What makes the cervical and lumbar segments more lordotic than thoracic and sacral?

Answer 8

IVD is thicker anteriorly
IVD is uniform in thoracic

Question 9

CV junction

Answer 9

atlax, axis and head

Question 10

CT junction

Answer 10

mobile lower cervical movement meets super stiff thoracic t-spine

note: upper cervical spine is more mobile than the lower

Question 11

the most rotation occuring at a junction is at

Answer 11

Thoracolumbar junction

thoracic has a larger ability to rotate than lumbar

Question 12

lumbosacral junction

Answer 12

mobile l spine meets stiff SIJ ..
LESS ROTATION

Question 13

two types of spinal stability

Answer 13

mechanical (static) stability = when body is still (equilibrium)

conrolled (dynamic) stability
- passive system= resisting forces of translation, compresson and torsion (esp at end range)
- active system= mm coordination to control body relative to environment
- CNS= feedforward/feedback

Question 14

function equals=

Answer 14

local mobility
global stability

Question 14

if the passive system is damaged

Answer 14

active system picks up slack, hence fatigues quicker

Question 15

open pack position of the lumbar spine

Answer 15

midway flx/ext

Question 16

close packed position of lumbar s

Answer 16

full ext

Question 17

capsular patter of lumbar s (limitations)

Answer 17

SB = Rotation, Extension

more info slide 13

Question 18

lumbarization
(less common)

Answer 18

S1 more mobile

more info slide 13

Question 19

sacralization

Answer 19

L5 fuses to sacrum

more info slide 13

Question 20

how much axial load do the facets carry with a normal intact disc carry?
how about a degenerated disc?

Answer 20

normal = 20-25%
degenerated disc = facets take up to 70% of axial load

more info slide 14

Question 21

anterior facet joint capsule formed by
facet joints are reinforced by__

Answer 21

anterior = ligamentum flavum
reinforced by: multifidus and ligamantum flavum

Question 22

facet joints are tight in

Answer 22

ALL POSITIONS

Question 23

how does the fibroadipose meniscoid “buckle”

Answer 23

buckles during flexion and “lodges” under the capsule

it blocks extension which causes acute “locking”

Question 24

the structure that absorbs shock and distributes load (compression)

Answer 24

IV disc

Question 25

Annulus fibrosus surrounds the NP with neurovacular supply to ___ attached to ___ transmitting (3) forces ____H20

Answer 25

- outer 1/3 - end plates - compression, shear, torsion - 60-70%

Question 26

which AF zone bas the most fibrocartilage?

Answer 26

inner zone

Question 27

Nucleus pulposus: - % H20 - NO _ - Absorbs___ and__ forces

Answer 27

70-90% NO BLOOD AND NERVE SUPPLY absorb compression and shear

Question 28

what structure isweak to resist compression?

Answer 28

end-plate b/c mostly has no blood/nerve

Question 29

if the IV disc is avascular, how does it recieve nutrients?

Answer 29

by diffusion via end-plates (cartilaginous)

Question 30

everytime there's a compression/tracton to the spine, blood goes

Answer 30

away from bone and to disc via endplate

Question 31

D/T lumbosacral angle, L5 tends to slide __and___

Answer 31

ant and inf ## Footnote more info slide 20 (spondy)

Question 32

greatest tensile strength in lumbar region, resisting extension and excessive lordosis

Answer 32

ALL

Question 33

resistns flexion and traction and is weak in the lumbar region and causes HNP

Answer 33

PLL

Question 34

resising flexion ; **slack only w/ extension strongest in lumbar region

Answer 34

ligamentum flavum

Question 35

posterior ligaments interspionous ligament and supraspinous ligaments

Answer 35

resists hyperflexion

Question 36

intertransverse ligaments

Answer 36

limit contrallateral flexion (side bend)

Question 37

iliolumbar ligament

Answer 37

resist ipsilateral side bend and translation of L5

Question 38

Superior band of iliolumbar ligament

Answer 38

prevents flexion

Question 39

inferior band of iliolumbar ligament

Answer 39

taut in extension

Question 40

posterior band of iliiolumbar ligament

Answer 40

prevents flexion and resist side bending at L4, stabilzing L5 from ant displacement

Question 41

the activation of this mm increases fascial tension, causes limitation intersegmental mobility and ant translation

Answer 41

TA (in relation to thoracolumbar fascia)

Question 42

thoracolumbar fascia functions

Answer 42

- mm attach - resisted segmental flexion - assist transmission of extension during lifting

Question 43

which mm is most effective in side bendig in the ES group?

Answer 43

iliocostalis

Question 44

***this mm is the "rotator cuff: of facet joint: produces compression force during contraction and will stabilize the facet joint***

Answer 44

multifidi

Question 45

review the slides ## Footnote 31-35

Answer 45

slide 31-35

Question 46

during axial compression:

Answer 46

NP pressure rise and AF bulges (posteroir or posterior lat) end plate bows foward vertebra and can fracture if the load is too quick (weakest) **Disc: squeez out H2o during axial compression and "shortens"**

Question 47

T/F facet joint sustains verticlaly applied load in neutral position

Answer 47

FALSE | severe axial compression overtime will lead to fatigue failure. ## Footnote more info slide 37

Question 48

intradiscal pressures bending fwd and lifting 20 kg weight w/back bent and knees straight lifting 20 kg weight w/ back straight and knees bent

Answer 48

150% 169% 73%

Question 49

facet joints are strong during ____

Answer 49

traction creep 1-2 mm immediately lenghening will cause flattening of lumbar lordosis curve

Question 50

"opening" movementof the lumbar spine is flexion occurs in all segments except

Answer 50

anterior rock + anterior translation L5-S1

Question 51

flexion is restained due to

Answer 51

joint capsule (mainly) IV disc

Question 52

this motion increases the risk of damaging annulus fibrosus

Answer 52

rotation in flexion b/c facets are minimal contact

Question 53

axial rotation restrains

Answer 53

interspinous and supraspinous lig

Question 54

interspinous ligament buckles b/t SPs during

Answer 54

extension

Question 55

read the last couple of slides