Spinal Biomechanics Flashcards

1
Q

What is the definition of a plane and what are the three planes of space?

A

a flat surface determined by the position of three points in space.
sagittal, frontal, transverse

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2
Q

What motions occur in the sagittal plane? What axis (X, Y or Z) is this plane in?

A

flexion and extension

The X-axis

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3
Q

What motions occur in the frontal (coronal) plane? What axis (X, Y or Z) is this plane in?

A

right lateral and left lateral flexion

Z-axis

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4
Q

What motions occur in the transverse (axial) plane?What axis (X, Y or Z) is this plane in?

A

rotation

Y axis

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5
Q

What is the definition of an axis?

A

a line around which rotary movement takes place or along which translation occurs

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6
Q

What are degrees of freedom?

A

the number of ways in which a body can move

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7
Q

How many degress of freedom are seen in spinal segments?

A

6

3 translations, 3 rotations

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8
Q

What is the instantaneous axis of rotation?

A

a point in the body, or some hypothetical extension of it that does not move when the body moves in a plane

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9
Q

What is a motion segment? What is it comprised of in the spine?

A

the functional unit/ smallest spinal segment exhibiting biomechanic characteristics of the rest of the spine.
=two adjacent vertebrae, their interconnecting disc, joint, capsule and ligaments

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10
Q

What is coupled motion?

A

two motions occurring at the same time around two different axes. one motion cannot be produced without the other

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11
Q

What is a loose-packed joint position and what is this position for the spine?

A

position at which the joint capsule and ligaments are most relaxed and maximum joint play is possible. articulating surfaces are maximally separated.
eg. Spine: halfway between flexion and extension

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12
Q

What is a closed-packed position?

A

capsule and ligaments maximally tightened, no joint play, maximum contact between articular surfaces.
eg: Spinal extension at the facet joint (other examples slide 237)

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13
Q

How many vertebra do we have in total? how many are in each segment of the spine?

A
33 vertebrae
7 cervical
12 thoracic (kyphosis)
5 lumbar (lordosis)
5 sacral
5 coccygeal
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14
Q

Which area of the spine has the greatest flexion/extension ROM?

A

lower cervical (second best is lower lumbar)

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15
Q

Which area of the spine has the greatest axial rotation ROM?

A

upper cervical

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16
Q

What direction do the condyles of the occiput face? Are they convex or concave? What do they articulate with?

A

face laterally and inferiorly
convex rockers
articulate with superior articular facet of C1

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17
Q

What direction do the facets of C1 face? Are they convex or concave? What do they articulate with?

A

face medially and superiorly
concave surface
articulate with the occipital condyles

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18
Q

What is occuring at the occiput during flexion and extension of the C0-C1 joint? What degree of flexion/extension occurs?

A

flexion: occiput glides posteriorly (10 deg)
extension: occiput rolls anteriorly (25 deg)

*note: the greatest range of motion occurs at the C0-C1 joint

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19
Q

During lateral flexion of the C0-C2 joint, the occiput glides on the (opposite/same) side. What degree of lateral flexion occurs?

A

opposite. 5 deg

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20
Q

During C0-C1 rotation, the occiput glides (ant./post. eriorly) on the side of rotation and (ant./post.) on the side opposite of rotation. What limits this motion and what is the degree of ROM?

A

posteriorly on the side of rotation, anteriorly on the side opposite of rotation.
The alar ligament limits this ROM to 5 deg on each side

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21
Q

How many facet joints are at the C1-C2 joint?

A

3

2 facet joints and the atlas-odontoid joint

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22
Q

What kind of joint is the atlas-odontoid joint?

A

synovial

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23
Q

What ligaments comprise the odontoid joint? (4)

A

occipital-odontoid ligament, atlas-odontoid ligament, alar ligament, transverse ligament

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24
Q

In flexion, the C1 articular surfaces glide (ant./post.).

In extension, the C1 articular surfaces glide (ant.post.)

A

in flexion, C1 surfaces glide posteriorly

in extension, the C2 surfaces glide anteriorly

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25
Q

In lateral flexion of the C1-C2 joint, the articular surfaces of C1 glide on the C2 articular surfaces (toward/away from) the side of lateral flexion? What is the ROM deg?

A

in lateral flexion, C1 glides toward the side of flexion, with 5 deg of ROM.

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26
Q

Rotation of which joint accounts for approximately half of cervical rotation? The first ______ degrees of rotation occur exclusively at this joint.

A

the C1-C2 rotation- the first 25 degrees of cervical rotation occur here.

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27
Q

During C1-C2 rotation, C1 surface glides ______ on the side of rotation and _____ on the side opposite rotation. (anterior/posterior)

A

C1 glides posterior on the side of rotation and anterior on the side opposite rotation.

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28
Q

C2 flexion and extension is primarily what type of motion?

A

translation

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29
Q

When c2 is compressed anteriorly and distracted posteriorly, with facets gliding apart and joint gapping, the neck is in what type of motion?

A

flexion (also, same occurs in C3-C7)

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30
Q

When c2 is distracted anteriorly and compressed posteriorly, with approximated facets and compression of inferior margins, the neck is in what type of motion?

A

extension (also, same occurs in C3-C7)

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31
Q

What are two structural differences between C1/C2 vertebrae and C3-C7 vertebrae?

A

wide transverse body size

transverse foramen for the vertebral arteries

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32
Q

articular facets of the C3-C7 vertebrae are at a ______ deg angle with the transverse plane and ______(parallel/perpendicular) to the frontal/coronal plane.

A

45 deg angle to the transverse plane

parallel to the frontal plane

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33
Q

The joints of Luschka form at age ____ and complete forming by age ______. What is another name for the joints of Luschka?

A

6-9, completing at age 18

uncinate process

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34
Q

What is the purpose of the Joint of Luschka? What motions do they couple?

A

limits lateral flexion,

couples lateral flexion with rotation

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35
Q

The cervical curve is ______(lordotic/kyphotic) at ____ degrees. and it is a (secondary/primary) curve?

A

lordotic at 20-50 degrees

a secondary curve

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36
Q

The cervical disc height to body ratio is:_______, allowing for:___________

A

2:5, allowing for greater range of motion

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37
Q

cervical discs are higher _____-(anteriorly/posteriorly), causing the nucleus pulposus to be slightly ________ (anterior/posterior) to center.

A

cervical discs are higher anteriorly (contributing to lordosis),

thus the nucleus pulposus is slightly posterior

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38
Q

The average ROM in flexion/extension in the lower cervicals is:

A

15 degrees (highest is mid cervicals, 20 degrees; lowest is C2-3/ C7-T1 with 10 degrees)

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39
Q

flexion/extension at the lower cervicals is a combination of what two types of movement?

A

segmental tipping (sagittal rotation) and gliding (sagittal translation)

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40
Q

The average lateral flexion ROM at the cervical disc is _____ degrees.

A

7-8 degrees

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41
Q

lateral flexion of the cervical spine is coupled with what motion?

A

ipsilateral axial rotation

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42
Q

lateral flexion and coupled rotation of the cervical spine decreases as one moves (caudally/rostrally)?

A

caudally

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43
Q

During lateral flexion of the lower cervical spine, disc wedging and approximation occur ______ and distraction is present on the _____. (which side of lateral flexion?)

A

wedging and approximation occur on the same side of lateral flexion
distraction occurs on the opposite side of lateral flexion

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44
Q

facets glide down and medially ipsilaterally and glide up and laterally contralaterally in the lower cervical spine. what motion is occuring?

A

lateral flexion

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45
Q

average ROM for lower cervical rotation is:

A

5 degrees

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46
Q

axial rotation of the lower cervical spine is coupled with what motion?

A

ipsilateral lateral flexion

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47
Q

During lower cervical rotation: on the side of rotation the inferior facets glide:-________ and ______
on the opposite side of rotation the inferior facets glide:______ and ______

A

on the side of rotation, they glide down and medially

on the opposite side of rotation, they glide up and laterally

48
Q

What are two properties of thoracic vertebrae shape?

A

TPs are thick, strong, long

SP are long and slender

49
Q

What are two facet joints on thoracic vertebrae that articulate with the ribs?

A
Costovertebral joint ( rib heads)
Costotransverse joints (rib tubercles)
50
Q

Thoracic articular facets for a ____ degree angle from the transverse to the coronal plane and a _____ degree angle from the coronal towards the Sagittal plane.

A

60

20

51
Q

Inferior thoracic facets face _______, _________ and _______-ly

A

Inferiorly, medially and anteriorly

52
Q

Superior thoracic facets face ______, ________ and _______-ly

A

Superiorly, laterally and posteriorly

53
Q

Which thoracic vertebrae articulate atypically? What type of vertebrae do they act more like?

A

T1 acts more like C7

T11 and 12 act more like lumbar

54
Q

The thoracic is a _______ curve, at _____ degrees. Is it a primary or secondary curve? Where is the curves apex?

A

Kyphotic at 20-50degrees. Primary curve, with apex at T6-7

55
Q

Flattening of the thoracic curve will cause what three things?

A

Decreased cervical curve
Cervical curve shifts forward
Increased lumbar curve

56
Q

What is the thoracic body height: disc ratio? Is the thoracic spine more or less flexible? Where is the nucleus pulposus located?

A

1:5
Least flexible part of the spine
N. Pulposus is centrally located

57
Q

What is the degree of flexion in the thoracic spine?

A

Average 6
Upper thoracic: 4
Middle: 6
Lower thoracic: 12

58
Q

What two motions are coupled during spinal flexion?

A

Sagittal rotation and Sagittal translation

59
Q

What happens to thoracic discs and facets during flexion?

A

Facets glide apart, disc opens posteriorly

60
Q

What happens to thoracic facets and discs during extension?

A

Facet joints and posterior discs approximate

61
Q

Thoracic lateral flexion is about _____ degrees of ROM. What movement is coupled with thoracic lateral flexion?

A

6 degrees

Coupled with axial rotation. Ipsilateral in upper Thoracics, but can be to both sides in lower thoracics

62
Q

How do thoracic discs and facets move during lateral flexion? What is unique to upper thoracic motion?

A

Discs and facets approximate on the side of flexion, separate on opposite side.
In upper thoracic, discs glide medially on the side of flexion and laterally on opposite side

63
Q

What is the average ROM degree in upper thoracic rotation?

A

8-9 degrees

64
Q

upper thoracic rotation is coupled with:

A

same side lateral flexion

65
Q

during thoracic rotation, inferior facets glide______ on the same side of rotation and _____ on the opposite side of rotation.

A

inferiorly on the same side

superiorly on the opposite side

66
Q

What is the pump-handle movement of the ribs, and what does this movement do to the A-P diameter of the rib-cage?

A

rib head rolls downward, elevating the anterior portion of the rib
this increases the A-P diameter of the ribcage

67
Q

What is the bucket-handle action on the rib-cage and what does this action do to the shape of the rib cage?

A

ribs elevate on TPs

this increased the transverse diameter of the rib cage

68
Q

What is the Caliper-action on the rib cage and what does this movement do to the shape of the ribcage?

A

ribs move apart from each other with inspiration

this increases the lateral diameter of the ribcage

69
Q

What are four characteristics of lumbar vertebrae (SPs/TP characteristics, etc)?

A

short, broad, strong pedicles and laminae
thick, broad SPs
long, slender, flattened TPs
Mammillary processes

70
Q

lumber articular facets are primarily in the _____ plane, but become more _____ and the lumbosacral junction

A

primarily in the sagittal plane but become more coronal

71
Q

What is the greatest flexibility in the lumbar spine?

A

flexion/extension (facet orientation limits rotational flexibility)

72
Q

The lumbar curve is a ______ (kyphotic/lordotic?) curve at ___-____ degrees. Where is it’s apex, and is it a primary or secondary curve?

A

lordotic curve at 20-60 degrees.
apex at L3-L4
a secondary curve (in response to standing)

73
Q

An anterior pelvic tilt ________ (increases/decreases) lordosis. A posterior pelvic tilt ________ (increases/decreases) lordosis.

A

anterior tilt increases lordosis

posterior tilt decreases lordosis

74
Q

What is the lumbar disc height:body ratio? Where is the nucleus pulposus? What two things do these characteristics allow the lumbar spine to do?

A

1:3, with N.pulposus posteriorly.
allows for movement
allows resistance to axial compression forces

75
Q

What is the process of force transmission through a disc that allows stable weight-bearing?

A
  1. compression raises n.pulposus hydrostatic pressure
    - ->elevated annular fibrosis pressure
    - -> inhibits radial expansion of a. fibrosis
    - ->increased upward/downward nuclear pressure
76
Q

What is a disc bulge? What does it cause?

A

generalized extension of disc tissues beyond the edges of the vertebral body <3mm (NOT A HERNIATION). May compress neural tissue causing pain and joint dysfunction

77
Q

What are two types of bulging discs? Which one is found in scoliosis?

A

symmetrical and asymmetrical (found in scoliosis)

78
Q

What is a disc herniation?

A

when n.pulposus ruptures through the a.fibrosis. causing an inflammatory response and compressing neural tissue. may cause radicular and somatic pain
A localized process involving <50% of disc circumference

79
Q

What is a focal herniation?

A

A herniation that involves <25% of disc circumference

80
Q

What is a broad-based herniation?

A

A herniation that involves between 25-50% of the disc circumference

81
Q

What two forms may herniated discs take?

A

protrusion (base of herniation is greater than distance of protrusion) and extrusion (disc material balloons out as if budding off)

82
Q

What are three types of annular tears? What three things might these cause?

A

radial, transverse, concentric tears (fissures)

  • weaken the disc
  • generate pain
  • disc material may migrate into tears
83
Q

lumbar segment combined flexion/extension ROM is;

A

15 degrees

84
Q

during lumbar flexion vertebra tilts and slides ______ (ant/post) facets glide ______ (sup/inf?) disc is compressed _______(ant/post?) and stretched _______ (ant/post?)

A

vertebra tilts and slides anteriorly… facets glide superiorly …disc is compressed anteriorly and stretched posteriorly

85
Q

during lumbar extension, vertebra tilts and slides ______ (ant/post) facets _______ (approximate/distract), facet capsule, disc and anterior longitudinal ligament are _______ (stretched/relaxed)___________(anteriorly/posteriorly?)

A

extension …vertebra tilts posteriorly … facets approximate … facet capsule, disc and anterior longitudinal ligament are stretched anteriorly

86
Q

Lumbar lateral flexion ROM averages about _____ on each side. The lumbosacral joint only has _____ degrees ROM.

A

6 degrees

3 degrees at lumbosacral jiont

87
Q

lumbar lateral rotation is coupled with:

A

opposite side rotation (OPPOSITE OF CERVICAL AND THORACIC)

88
Q

during lumbar lateral flexion facets glide ______ on the side of flexion and _____ on the opposite side (apart/together)

A

together on the side of flexion

apart on the opposite side

89
Q

Lumbar rotation ROM is only ______ degrees. What limits this rotation?

A

2 degrees, limited by facet joints

90
Q

Lumbar rotation is coupled with what two motions?

A

lateral flexion and slight sagittal plane rotation

91
Q

rotation of L1-L3 is coupled with _____ lateral rotation, whereas rotation of L4-L5 is coupled with _______lateral flexion (same side/opposite side)

A

L1-L3 rotation opposite side lateral rotation

L4-L5 rotation same side lateral rotation

92
Q

What bones and features are in the pelvis (3) and What are two joints in the pelvis?

A

innominate bones, sacrum and the pubic symphisis
lumbosacral joint
sacroiliac joints

93
Q

The innominate is a fusion of what three bones?

A

ilium, ischium, pubis

94
Q

What type of joint is the pubic symphisis? how movable is it?

A

amphiarthrosis joint (slightly moveable) with a fibrocartilaginous disc

95
Q

What type of nerves exit the sacral formina?

A

autonomic parasympathetic

96
Q

What type of joint is the sacroiliac joint?

A

part fibrous and part synovial (diarthrosis)

97
Q

Heavy ligametnous attachments of the sacroiliac joint are on the _______ and ______ surfaces.

A

(posterior and superior)

98
Q

What are four characteristics of the articular surface of the sacrum in the sacro-iliac joint?

A

diarthrosis
L-shaped
hyaline articular cartilage
central concave groove

99
Q

What ligament in the sacroiliac joint can calcify with age, leading to immobility and pain?

A

the iliolumbar ligament

100
Q

What is the “Z” joint?

A

the L5-S1 zygapophysial joint

101
Q

Name the 8 ligaments of the posterior pelvis

A
posterior sacroiliac lig.
sacrotuberous lig
superficial dorsal sacrococcygeal lig.
sacrospinous lig.
deep dorsal sacrococcygeal lig.
dorsal sacroiliac lig.
interosseous sacroiliac lig
iliolumbar lig.
102
Q

inferior displacement of the pelvis is prevented by:

A

the wedge shape of the pelvis

103
Q

posterior displacement of the pelvis is prevented by:

A

sacroiliac ligaments

104
Q

anterior displacement of the pelvis is prevented by:

A

sacroiliac ligaments and the pubic symphysis

105
Q

What is meant by “form closure” of the pelvis?

A

the anatomy of the SI joints promotes stability

wedge shape, interlocking grooves and S-shaped joint surfaces, eg.

106
Q

What is meant by force closure of the pelvis?

A

tension in muscles, ligaments and fascia aids in stabilizing the SI joints.
creates lateral-medial pressure (“X” shaped muscles across the back)

107
Q

What is the function of pevic dynamics?

A

as a shock absorber, to absorb and adapt to forces

108
Q

What is meant by “nutation” of the SI joint?

A

the sacral base rotates anteriorly on the ilium/ the ilium rotates posteriorly on the sacrum

109
Q

What is meant by counternutation of the SI joint?

A

the sacral base rotates posteriorly on the ilium/the ilium rotates anteriorly on the sacrum

110
Q

What are three things that are caused by moving into nutation?

A

anterior sacral tilt, posterior iliac rotation, increased lumbar lordotic curve

111
Q

What are three things that are caused by moving into counternutation?

A

posterior sacral tilt
anterior iliac rotation
decreased lumbar lordotic curve

112
Q

What are four ways in which the pubic symphysis can move?

A

compression, distraction
rotation in sagittal plane with SI joint motion
gliding (translation) in anterior/posterior and superior inferior directions

113
Q

During hip flexion, the PSIS moves _____ and _____, accompanied by ipsilateral ______ movement of the sacral base.

A

PSIS moves posteriorly and inferiorly

sacral base moves anteriorly and inferiorly

114
Q

During hip extenion, the PSIS moves _____ and ________ly, accompanied by ipsilaterl ______ movement of the sacral base.

A

PSIS moves anteriorly and superiorly

sacral base moves posteriorly and superiorly

115
Q

An anterior pelvic tilt can be caused by contractions of what three muscles?

A

rectus femoris, iliopsoas, erector spinae

116
Q

A posterior pelvic tilt can be caused by contraction of what 4 muscles?

A

gluteus maximus
hamstrings
rectus abdominus
obliquus externus abdominis