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GM Biomechanics > Exam 2: Lumbar Spine > Flashcards

Exam 2: Lumbar Spine Flashcards

(83 cards)

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1
Q

What are the main responsibilities of the lumbar spine

A

Bears large loads, used for powerful muscle actions, trunk mobility, significant biomehcanical needs

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2
Q

What are the characteristics of lumbar facets

A

Thick large and strong

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3
Q

The inferior articular processes of lumbars are ____ and face _____

A

Convex; anterolaterally

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4
Q

The superior articular processes of the lumbars are ____ and face ____

A

Concave; posteromedially

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5
Q

Lumbar facets lie primarily in what plane

A

Sagittal, becoming more coronal at lumbosacral joint

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6
Q

What is a developmental abnormality where one facet faces sagitally and the other facet faces coronally and where is it mc

A

Facet tropism mc L5-S1 then L4-L5

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7
Q

Facet configuration in the lumbars limits ____ and allows for greater _____

A

Limits rotational flexibility and allows for greater mobility in flexion and extension

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8
Q

Which lumbar facets have sagittal orientation and limit axial rotation (theta Y)

A

L1-L4 facets

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9
Q

Which facets are in a coronal orientation and limit posterior/anterior shear (z translation)

A

L5-S1 facets

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10
Q

The lumbar facets normally carry ___ of axial load and up to ____ in extension

A

18%; 33%

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11
Q

What is the primary movement in l/s

A

Flexion/extension

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12
Q

What percentage of trunk flexion/extension takes place in l/s

A

75%; twice as much flexion as extension

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13
Q

What is limited due to sagittal facet orientation

A

Axial rotation

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14
Q

Lateral bending is controlled primarily by what

A

Eccentric activity of the QL

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15
Q

Normal muscular activity leads to spinous processes rotation toward what

A

Side of lateral extension, spinous to ipsilateral side can switch at L4/L5

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16
Q

The nucleus of lumbar IVD are localized somewhat _____ in the disc

A

Posteriorly

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17
Q

What is the disc height to body height ratio of the lumbar IVD

A

1:3

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18
Q

The ratio of 1:3 in the lumbars allow more movement than ____ but less than ____ and gives the disc greater resistance to ____

A

T/s; c/s; axial compressive forces

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19
Q

Lumbar spinal canal contains enlargement of spinal cord proximally called what

A

Conus medularis and the cauda equina with spinal nerves distally

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20
Q

CNS is tethered to the coccyx by what

A

Filum terminale

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21
Q

Where does the spinal cord end

A

L2

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22
Q

After the spinal cord ends the nerve roots continue down the spinal canal as what

A

Cauda equina

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23
Q

Nerve roots in lumbars exit the dura how

A

Slightly above the foraminal opening

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24
Q

What does the exit of the nerve roots at the dura cause

A

Causes their course to be more oblique and length to increase

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25
When does the secondary lumbar lordotic curve begin to develop
Starts developing 9-12 months of age/beginning to sit up
26
When does the secondary lumbar lordotic curve become established
When learning to stand at about 18 months
27
Where is the apex of the lumbar lordotic curve
L3/L4 disc
28
Normal lumbar lordosis should be how many degrees
20-60 degrees
29
Changes in the sacral base angle can influence the depth of what
A-P curves in the spine
30
Sacral base angle increase with what
Anterior pelvic tilt
31
Anterior pelvic tilt increases the sacral base angle and causes lumbar lordosis, and weight bearing responsibilities how
Increases the lumbar lordosis which places more weight bearing responsibility on the facets
32
The sacral base angle decreases with what
With posterior pelvic tilt
33
Posterior pelvic tilt causes a decrease in the sacral base angle resulting in what impact on lumbar lordosis and weight bearing responsibilities
Results in decrease in the lumbar lordosis placing more weight bearing responsiblity on the disc and decreases the spines ability to absorb axial compressive forces
34
What is the major stabilizer of the L/s
The quadratus lumborum
35
When is the QL most active
During heavy lifting but is active in flex/extend, and lateral bend
36
Identify when the QL is more active between heavy lifts, isometric lateral bending holds, during standing isometric twists
Heavy lifts> isometric lateral bend holds > during standing isometric twists
37
What ligaments restrict excessive flexion/extension
ALL/PLL
38
What ligament is highly elastic and acts as a barrier to material that would otherwise enncroach on the cord during range of motion
Ligamentum flavum
39
What ligament acts like a larger extensor retinaculum to constrain long tendons of thoracic and lumbar extensors
Lumbodorsal fascia
40
What ligament acts like a collateral ligament and controls vertebral rotation to follow an arc through flexion range, also assist facet to remain in contact with rotation
Interspinous
41
What ligament guards against posterior shear
Interspinous
42
What ligament provides resistance against excessive forward flexion
Supraspinous
43
What well developed ligament restricts joint flexion, restricts distraction of facet surfaces during axial rotation
Facet capusle
44
What is the cascade of ligament damage
Trauma causes damage leading to laxity leading to joint degeneration
45
Which is more resistant to compressive forces: IVD or posterior facets
IVD = 80% resist of axial force, posterior facets = 10% of axial forces
46
What loading causes a symmetric stress distribution on the IVD
Eccentric loading
47
How much increase is there in resistance to axial forces in flexion and extenion in posterior facets
Increase 5x in flexion, incrreases 3x in extension
48
There is significant increase in disc pressure with what type of sitting
Straightened or flexed sitting
49
What motion increases tensile force at the anterior annulus and increases loading and compression of the posterior facets with a 3x increase in posterior facet compression forces
Extension
50
What motion increase posterior annulus tensile forces and decreases the spines ability to absorb axial compression and 5x increase in A-P shear on the posterior facets
Flexion
51
What motion decreases disc inhibition and metabolism, reduces disc height and increases annulus stress, increases mechanical load to posterior joints
Static loading
52
What causes a spondylolisthesis
Defect of the pars interarticularis
53
Spondylolisthesis fracture may come from repeatedly alternating flexion and extension movements especially what
Hyper extension
54
Who and where is spondylolisthesis likely to occur
Usually at L5 in males
55
What spondy is developmental abnormality of neural arch resulting in deformity and anterior vertebral dispalcement
Congenital
56
What spondy class is a defect in pars interarticularis (stress fx) mc in younger paitents at L5
Isthmic
57
What type of spondy has segmentally instability secondary to advanced DDD and posterior DJD, mc in older patients (women over 60 esp) and typically occurs at L4
Degenerative
58
What type of spondy class is an acute fix involving neural arch but NOT pars interarticularis
Traumatic
59
What spondy type is an osseous deformity secondary to local or systematic pathology (pagets mets, osteoporosis)
Pathologic
60
What grades of spondy can we adjust
Grades 1/2
61
What is the grading system of spondy’s called
Meyerding grading system
62
How much movement means instability in a spondy
>3.5 mm of movement in flexion/extension
63
What fracture is a comminuted vertebral body fracture with disruption of the anterior and posterior walls of the VB
Burst fracture
64
What does a burst fracture cause
Sever neuro problems from retropulsion of bone into spinal canal
65
What causes a burst fracture
Results from high energy axial load like trafffic collision, high falls, seizures somtimes
66
What type of complex is the pelvic joint
3 joint complex
67
What type of joint is the SI
Mobile synovial joints
68
What do pelvic joints do
Support trunk, guide movement, help absorb the compressive forces with locomotion/weight bearing
69
Surface contours of the pelvis develop into what
Interlocking elevations and depressions
70
What type of effect does the pelvis produce on the sacrum
Keystone effect distributing axial compressive forces
71
At birth what are the joints of the SI like
Undeveloped, smooth, flat
72
After ____ the SI joint begins to take their adult characteristics
Ambulation
73
In the teen years what happens to the SI
The joint surfaces begin to roughen and develop characteristic grooves/ridges
74
In later year what pateints will have interarticular adhesions across the SI joints and have lost SI joint motion
Mostly males
75
When is the SI joints most activw
Locomotion in flex/extend along with hip joint
76
As the left innominate moves posteriorly/inferiorly the left sacral base moves how
Anteriorly/inferiorly (nutation)
77
As the right innominate moves anteriorly/superiorly, the sacral base moves how
Posteriorly and superiorly (counternutation)
78
The proposed axes of motion in the SI articulation allow what type of movement
Gyroscopic figure 8 movement
79
Is the SI joint crossed by muscle
No
80
What contributes to the strength of the joint capusle at SI and ligaments
The different muscles near the SI providing stability not mobility
81
What is the function of muscle at the SI
Not to generate motion but function as brace for the area and create stability for effective load transfer
82
What happens to theta x when saccrum apex goes posterior
Nutation = flexion malposition
83
What happens to theta x when saccrum base goes posterior
Counternutation = extension malposition

GM Biomechanics (5 decks)

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