Biomechanics Of Lumbar

Question 1

What are the 3 subsystems?

Answer 1

Control subsystem-Neural

Active subsystem-Spinal Muscles

Passive subsystem-Spinal Column

Question 2

What percentage of load is through the intervertebral body and interbody joint?

Answer 2

80%

Question 3

What percentage of load is through the posterior structures?

Answer 3

20% (ligamentum flavum)

Question 4

What is an annulus?

Answer 4

Concentric rings to contain nucleus pulposus

Question 5

What does the annulus provide?

Answer 5

Peripheral strength

Flexibility

Protection from distraction

Shear

Torsion

Question 6

What percentage of water in younger adults is the nucleus pulposus?

Answer 6

70-90%

Question 7

What is the nucleus pulposus?

Answer 7

Shock absorber

Question 8

What can dehydrated discs increase?

Answer 8

Load to facet joints

Question 9

What happens when the nucleus pulposus becomes depressurized due to age?

Answer 9

Loses uniform cushioning and may bulge

Question 10

What type of joint is the zygapophyseal joint?

Answer 10

Synovial plane

Question 11

What movement does the zygapophyseal joint allow?

Answer 11

Flexion

Question 12

Why do zygapophyseal joints restrict excessive flexion?

Answer 12

To protect IVD

Question 13

What does the zygapophyseal joint block?

Answer 13

Excessive anterior translation

Question 14

What is the ROM of lumbar axial rotation?

Answer 14

5-7°

Question 15

What is the ROM of lumbar rotation limited by?

Answer 15

Sagittal plane alignment

Facet joints

Facet separation

Question 16

What is the ROM of lumbar lateral flexion?

Answer 16

20°

Question 17

What is the role of intrinsic muscles?

Answer 17

Precision control (high degree of muscle spindles)

Question 18

What is the role of extrinsic muscles?

Answer 18

Coarse control, stabilization, and torque production

Question 19

What is the role of the diaphragm and pelvic floor?

Answer 19

Maintain intraabdominal pressure for stability

Question 20

Why does the neural subsystem receive input from passive and active subsystems?

Answer 20

To determine requirement for maintaining stability

Question 21

What are the general tissues and structures that provide passive support to the lumbar spine?

Answer 21

Bones

Ligaments

Intervertebral discs

Question 22

What general patterns of positioning and action result in increasing intradiscal pressure?

Answer 22

Pressure is most increased when carrying and lifting objects with the least amount of pressure when lying down or reclining

Question 23

Which anatomical structures compose the motion segment?

Answer 23

Superior vertebrae

Intervertebral disc

Interbody joint

Inferior vertebrae

Facet joint

Question 24

What determines the labeling of anatomical movement of the motion segment?

Answer 24

When naming, we name based on how the superior vertebrae moves on the inferior vertebrae

And based on the direction of the anterior surface of the vertebral body

Question 25

Explain the effect of spinal flexion on the neural and central foraminal openings?

Answer 25

Separation of the spinal processes increasing the diameter of the neural foramen and spinal canal

Question 26

Explain the effect of spinal extension on the neural and central foramina openings?

Answer 26

Closing of the facet joints, narrowing the lateral neural foramen

Question 27

What is the normal total spinal flexion ROM required to be normal?

Answer 27

45-50 degress

Question 28

What’s the normal total spinal extension ROM?

Answer 28

15-25 degrees

Question 29

What is forward bending?

Answer 29

Lumbar flexion followed by anterior pelvic tilt

Question 30

What is returning to upright?

Answer 30

Posterior pelvic tilt followed by lumbar extension

Question 31

How might manual therapies impact the 3 subsystems?

Answer 31

Helps retrain the system continuing form localized stabilization to general stabilization and functional stabilization

Question 32

What does manual therapy ensure?

Answer 32

Patients have mobility, stability, and proprioception to be able to perform exercise

Question 33

What are the arthrokinematics of lumbar flexion?

Answer 33

Inferior articular facets of the superior vertebrae glide superiorly to open the facet joint (Superior vertebrae rolls anteriorly on inferior vertebrae)