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POTH 225 - Intro to Biomechanics > L10 - Lumbar Spine > Flashcards

L10 - Lumbar Spine Flashcards

1
Q

What forms the lumbar spine?

A
  1. Vertebrae
  2. Intervertebral discs

See NDC p.2 for illustration

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2
Q

Name the spinal curves + locations.

A
  1. Lordosis: cervical + lumbar
  2. Kyphosis: thoracic + sacral

See NDC p.3 for illustration

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3
Q

Name the parts of the vertebrae.

A
  1. Articular facets
  2. Vertebral body

See NDC p.4-5 for illustration

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4
Q

What is the function of the lumbar ligaments?

A
  1. Restrain movement
  2. Sensory - provide information about vertebrae position
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5
Q

Name the joints of the lumbar spine (2).

A
  1. Facet joints
  2. Intervertebral joint

See NDC p.7 for illustration

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6
Q

Describe the facet joints.
- type of joint
- what forms them?
- when does load increase?

A

Synovial joints
Superior articular process + Inferior articular process

Increase loading on facet with extension
–> when bending back, the block is the facet joint

See NDC p.7-8 for illustration

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7
Q

What is the functions of the facet joints. (4)

A
  1. Guide segmental motion
  2. Resist anterior shear: car accident, ski
  3. Resist torsion
  4. Resist compression

See NDC p.8 for illustration

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8
Q

What forms the intervertebral joints?
What is their functions?

A

Vertebrea bodies + vertebrea bodies via intervertebral disc

  1. Maintain space between vertebrae
  2. Allow movement
  3. Resist compression: landing from a jump
  4. Resist rotation

See NDC p.7,9 for illustration

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9
Q

Name the 2 parts of the intervertebral disc.

A
  1. Annulus fibrosus (S)
  2. Nucleus pulposus (D)

See NDC p.10-11 for illustration

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10
Q

Describe the annulus fibrosus.
- inner or outer
- rings: what, direction
- function

A

Outer portion
Rings of fibrocartilage, obliquely orientated

Function: Resist tensile forces and compression.

See NDC p.10-11 for illustration

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11
Q

Describe the nucleus pulposus
- inner or outer
- composition
- functions (2)

A

Inner portion
70-90% water

Functions:
1. Resist compression
2. Role in nutrition

See NDC p.10-11 for illustration

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12
Q

What are the 2 types of movements of the lumbar movements.

A
  1. 3 translations
  2. 3 rotations

See NDC p.13 for illustration

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13
Q

Name the 3 translations of the lumbar movement.

A

Three translations
1. Distraction/compression
2. Anterior/posterior shear
2. Left/right shear (glide)

See NDC p.13 for illustration

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14
Q

Name the 3 rotations of the lumbar movement.

A

Three rotations
1. Flexion/extension
2. Left/right sidebend (sideflexion, lateral flexion)
3. Left/right rotation

See NDC p.13 for illustration

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15
Q

What is the plane of the lumbar facet joints?
What movement does this person?

A

Lumbar facet joints more parallel to sagittal plane
than thoracic facets.

Function:
1. Allows flexion and extension
2. Limits rotations and sideflexion

See NDC p.14-15 for illustration

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16
Q

Describe the lumbar range of motion.
- flexion
- extension
- side bending
- rotation

A

Flexion: 35°-52°
Extension: 15°-29°
Side bending: 16°-25°
Rotation: 5°-16°

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17
Q

Movement of the Different Parts of the Spine
Which part of the vertebral column permits the most rotation?

A

Cervical spine
–> mostly C1-C2

See NDC p.18 for illustration

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18
Q

Movement of the Different Parts of the Spine
Describe the change in flexion/extension in the thoracic spine.

A

Compared to cervical spine, much less flexion/extension because of the ribs.

Flexion/extension increases at ribs 11-12 because they are floating ribs

See NDC p.18 for illustration

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19
Q

Movement of the Different Parts of the Spine
Describe the movement at the lumbar spine.

A

Good flexion/extension
A bit of side bending
No rotation

See NDC p.18 for illustration

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20
Q

Which part of the intervertebral disc moves during lumbar flexion/extension?
Describe F/E.

A

Nucleus pulposus moves with lumbar movement
- Lumbar flexion = posterior migration
- Lumbar extension = anterior migration

See NDC p.19 for illustration

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21
Q

What is the lumbopelvic rhythm?
Ex: touching our toes

A

Interplay between lumbar spine and pelvis when
moving

Example:
To touch your toes, lumbar spine flexes and pelvis
anteriorly rotates

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22
Q

What is the impact of tight hamstrings on the lumbopelvic rhythm?

A

Tight hamstrings posteriorly rotate the pelvis
So, to touch your toes = need to excessively flex the lumbar spine.
This can cause lumbar pain.

See NDC p.20 for illustration

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23
Q

What 2 structures resist lumbar rotation? (2)

A
  1. Annulus fibrosus
  2. Facet joints
    –> but provides less protection while in flexion
24
Q

When is injury to the annulus fibrosus more common?

A

Rotation + flexion
Less protection from facets while in flexion = increased risk of injury to annulus fibrosus

25
What is hoop stress?
Hoop stress: vertical load (compression) converted to circumferential tension. See NDC p.22 for illustration
26
What structures resists circumferential tension?
Hoop stress (compression --> circumferential tension) Circumferential tension resisted by annulus fibrosus and vertebral end plates
27
What are the lumbar joint reaction forces? (2) What causes these forces? (3)
1. Shear force 2. Compression force Forces on the vertebrae due to 1. gravity on trunk 2. loading in arms 3. muscles/ligaments usage
28
Name the lumbar injuries.
1. Spondylolysis 2. Spondylolisthesis 3. Disc herniation 4. Osteoporosis
29
Describe spondylolysis. - aka... - what - due to (2)
aka Scotty Dog facture Fracture of pars interarticularis (attachment of facet) Due to: 1. Large magnitude anterior shear (>2000N) 2. Due to repetitive lumbar extension and rotation See NDC p.25,27 for illustration
30
What sports are more common to have spondylolysis? Name them in order of prevalence. (7)
General Population 6% 1. Track and field- throwing 27% 2. Gymnastics 17% 3. Rowing 17% 4. Weightlifting- 13% 5. Judo- 11% 6. Volleyball- 10% 7. Track and field- running 7%
31
Describe the spondylolisthesis. - what - caused by...
Anterior displacement of a vertebrae. Spondylolysis can result in spondylolisthesis. See NDC p.28 for illustration
32
Describe disc herniation. - what - symptoms
Nucleus pulposus bulges through the annulus fibrosus Can impinge on nerve root 1. Weakness 2. Radiating pain 3. Sensory changes See NDC p.30,32
33
In what direction is disc herniation more common? What movement should be avoided? * Why
Disc herniation usually occurs posterior-lateral part of the disc. We want to avoid flexion : puts more pressure on the posterior disc See NDC p.30,32
34
When are people more likely to get a disc herniation? (3)
1. Injured near the end range of motion of flexion-rotation. --> ex: bending over to pick up something and move it 2. Does not have to be a high load 3. Associated with repetitive bending
35
In what age group are disc herniations more common?
Common in middle aged adults because of high water content = annulus fibrosus more jelly-like --> Low water content in older adults
36
Name the intradiscal pressure in these areas: * Lying supine * Standing * Coughing * Forward bending * Lifting 23lbs What is the implication for disc herniation?
Lying supine- 250 N Standing- 500 N Coughing- 700 N Forward bending- 1000 N Lifting 23lbs- 1700 N Higher intradiscal pressure = more pain if you have a disc herniation See NDC p.34 for graph relative to standing
37
Describe osteoporosis. - what - affects how many? - more common in...
Lose of bone mass (bone mineral density) Affects 100 million people worldwide Frequently after menopause in women
38
Osteoporosis What areas of the spine are more likely to have vertebral body compression fractures?
1. Thoracolumbar junction 2. Midthoracic spine
39
What is the prevalence of osteoporosis: - young VS old age - men VS women
Prevalence in women: <60 years: 3-17% >70 years: 19-46% Prevalence in men: <65 years: 2-8% >75years:15-21% BREF: more common in woman + more common in old age.
40
What happens to the ultimate failure point in osteoporosis?
The ultimate failure point (fracture point) occurs earlier on the stress/strain curve. See NDC p.37-38 for graphs
41
How is the ultimate failure point different in men VS women? How does it change with age?
The ultimate failure point is lower in women. In both, it decreases with age. See NDC p.39 for graph
42
REVIEW What are the functions of ligaments?
1. Attach bone to bone = stability 2. Proprioceptive input
43
REVIEW What is the definition of CREEP?
Constant applied load over time = tissue deformation See NDC p.40 for illustration
44
Does prolonged sitting result in low back pain?
It depends. For some it may cause pain, for others no problem
45
What does prolonged flexion cause? (slouched sitting)
1. Slow lengthening of lumbar ligaments (CREEP) 2. Increased range of motion 3. Impaired ligament sensory function 4. Altered muscle activation When sitting slouched your body doesn't consider it slouched
46
What are the 3 reports from sit-stand desks?
1. Sit-stand desk reduces sitting time by 80 mins/workday in healthy people (Graves 2015) 2. Prolonged standing did not decrease perceived low back pain vs. prolonged sitting in healthy adults (De Carvalho 2020) 3. Sit-stand desk reduced disability but not pain in patients with low back pain (Barone Gibbs 2018)
47
What is stoop lifting VS squat lifting? Describe shear forces in each.
Stoop = Lifting by flexing spine - Greater anterior shear forces - Greater load on ligaments Squat lifting = lifting with legs, “neutral spine” - Muscles provide a posterior shear force to limit the anterior shear
48
Describe the difference in shear force in lumbar spine in stoop lifting VS squat lifting.
Stoop lifting: 1635N Squat lifting: 1416N --> 200N more load on lumbar spine See NDC p.44 for complete table
49
Do lifting education programs decrease injuries from lifting?
Nope
50
SUMMARY Describe compression. - tissues loaded (3) - injury
1. Vertebrae body 2. Intervertebral disc 3. Muscles Injury: Vertebrae body or end plate fracture
51
SUMMARY Describe rotation/side bending. - tissues loaded (3) - injury
1. Facet 2. Pedicles 3. Muscles Injury: Pars interarticularis or pedicle fracture
52
SUMMARY Describe flexion. - tissues loaded (4) - injury (3)
1. Posterior ligaments 2. Posterior annulus fibrosis 3. Fascia 4. Muscles Injury: Annular tear, dis herniation, muscle injury
53
SUMMARY Describe extension. - tissues loaded (3) - injury
1. Anterior ligaments, 2. Posterior body elements 3. Muscles Injury: Pars interarticularis fracture, spondylolisthesis
54
How to prevent injury? (5)
1. Avoid repeated or prolonged end range lumbar flexion 2. Vary positions and loads 3. Allow time for tissues to restore normal length after prolonged loads 4. Do not sit too long (for some people) 5. Keep loads close
55
What is the flexion-relaxation phenomenon?
During full trunk flexion, relaxation of lumbar erector spinae muscles (i.e. reduction ) in healthy adults In full flexion, the load is supported by posterior disc/ligament structures.
56
Does flexion-relaxation happen in people with low back pain? Why? (2)
During full flexion, lumbar erector spinae muscles less likely to relax in patients with chronic low back pain Possible reasons 1. May act to protect injured disc/ligament/joints 2. May increase loading long-term

POTH 225 - Intro to Biomechanics (14 decks)

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