Lumbar Spine Flashcards Preview

Biomechanics Exam II > Lumbar Spine > Flashcards

Flashcards in Lumbar Spine Deck (42)
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1
Q

What is the most important characteristic of the lumbar spine?

A

Bear tremendous loads created by body weight

2
Q

What region of the spine is largely responsible for trunk mobility? ***

A

Lumbar spine

3
Q

In which way to the inferior articular processes of the lumbar spine fact?

A

Anterolaterally (convex)

4
Q

In which way to the superior articular processes of the lumbar spine fact?

A

Posteromedially (concave)

5
Q

What is a tropism?

A

Developmental abnormality where one facet faces sagittally and the other faces faces coronally

6
Q

Where does tropism usually occur in the lumbar spine?

A

Mostly L5-S1

Then L4-L5

7
Q

Lumbar facets primarily lie in what plane?

A

Sagittal plane

8
Q

When do facets become more coronal again after the lumbar spine?

A

Lumbosacral junction

9
Q

The facet configuration of the lumbar spine limits what movement and allows for great mobility of what movements?

A

Limits rotational flexibility

Allows greater flexion/extension

10
Q

The coronal facet orientation at L5-S1 limits what movement?

A

Posterior*/anterior shear (Z translation)

11
Q

What effect does hyperlordosis have on weight-bearing load of the lumbars?

A

Increases it

12
Q

What is the primary movement of the lumbar spine?

A

Flexion/extension (θX)

13
Q

Which occurs more in the lumbar spine: extension or flexion?

A

Flexion (2X)

14
Q

Why is axial rotation limited in the lumbar spine?

A

Sagittal facet orientation

15
Q

During lateral bending accompanied with axial rotation in the lumbar spine, to which direction does the spinous move?

A

Ipsilateral side (same)

16
Q

Why does the spinous move to the ipsilateral side in the lumbar spine during lateral bending coupled with axial rotation?

A

Eccentric lengthening of the quadratus lumborum

17
Q

In what area of the lumbar spine can the spinous sometimes switch and rotate to the contralateral side during lateral bending coupled with axial rotation?

A

L4 and L5

18
Q

What is the location of the nucleus pulposus in the lumbar spine?

A

Posterior

19
Q

What is the IVD height to vertebral body height ratio in the lumbar spine?

A

1:3 (middle compared to cervicals and thoracics)

20
Q

What is the purpose of the IVD height to body ratio of the lumbars being in the middle compared to cervicals and thoracics?

A

More movement than thoracics, less then cervicals

Greater resistance to axial compressive forces

21
Q

What does the lumbar spinal canal protect proximally?

A

Conus medullaris (enlargement of the spinal cord)

22
Q

What does the lumbar spinal canal protect distally?

A

Cauda equina (spinal nerves)

23
Q

What tethers the CNS to the coccyx?

A

Filum terminale

24
Q

At what vertebral level does the spinal cord end?

A

L2

25
Q

After the spinal cord ends at L2, what do the nerve roots continue as?

A

Cauda equina

26
Q

What structures are responsible for defining the range of motion and stabilizing the dural sac withing the foraminal canal?

A

Hoffman ligaments

27
Q

Although its movements are limited, how is the spinal cord able to demonstrate flexibility during different movements and activities?

A

Elastic deformation

28
Q

When does the lumbar curve start to develop?

A

About 9-12 months of age (as one begins to sit up)

29
Q

Where is the apex of the lumbar curve?

A

L3-4 disc

30
Q

When does the lumbar curve become established in nature?

A

About 18 months (as one begins to stand)

31
Q

What is the normal lumbar curve angle?

A

20-60 degrees

32
Q

What type of curve is the lumbar curve?

A

Secondary lordotic

33
Q

What are the effects on the sacral base angle with an anterior pelvic tilt? On the lumbar lordosis? Facets?

A

Increased sacral base angle
Increased lumbar lordosis
More weight bearing responsible on facets

34
Q

What are the effects on the sacral base angle with an posterior pelvic tilt? On the lumbar lordosis? Disc?

A

Decreased sacral base angle
Decreased lumbar lordosis
More weight bearing responsibility on disc

35
Q

A posterior pelvic tilt decreases the spine’s ability to absorb what kind of forces?

A

Axial compression

36
Q

What is the major stabilizer of the lumbar spine?

A

Quadratus lumborum

37
Q

The quadratus lumborum is always active during what motions?

A

Flexion, extension, lateral bending

38
Q

What do the ALL and PLL attach to?

A

Vertebral body and annulus

39
Q

What movements are restriction by the ALL and PLL?

A

ALL - extension

PLL - flexion

40
Q

What ligament is highly elastic and acts as a barrier to material that would otherwise encroach on the cord during range of motion?

A

Ligamentum flavum

41
Q

The lumbodorsal fascia is an attachment site for what muscles?

A

1 Transverse abdominis
2 Internal oblique
3 Latissimus dorsi

42
Q

The lumbodorsal fascia as as what kind of structure to constrain long tendons of thoracic and lumbar extensors?

A

Large extensor retinaculum