II: Biomechanics Of The Pelvis (PART 1/2) Flashcards Preview

Spinal Kinetics & Kinematics > II: Biomechanics Of The Pelvis (PART 1/2) > Flashcards

Flashcards in II: Biomechanics Of The Pelvis (PART 1/2) Deck (49):
1

Classification of the SI Joint

  • Diarthrodial joint (synovial)
  • Upper 1/3 is amphiarthrosis (ligamentous bridge)

2

Much of this kind of pain comes from SI problems:

Low back pain

3

What percentage of chronic low back pain is caused by SI problems?

10-26.6%

4

Major mechanical functions of pelvis:

  • Attaches spine to legs.
  • Transfers weight to legs.
  • Shock absorption.
  • Gyroscopic action during gait.
  • Females - birth.

5

Pelvis joints:

Q image thumb

  • 2 SI joints
  • Pubic symphysis

6

SI classified as this joint:

Diarthrodial or Synovial

7

Pubic symphysis classified as this kind of joint:

Fibrocartilaginous or Amphiarthrosis

8

Iliac surface has this cartilage:

Fibrocartilage

9

Sacral surface has this kind of cartilages:

Hyaline cartilage

10

What do intrinsic SI ligaments do?

bind sacrum to ilium

11

Muscles related to pelvic biomechanics:

Multifidus, erector spinae, hamstrings, gluteus maximus, piriformis, psoas, quadratus lumborum

12

What innervates the SI joint?

No one knows

13

What is the difference from male pelvis to female SI joint?

Female SI joint has less of an “S” = more mobility. Male SI joint has a more defined “S” shape and decreased mobility.

14

SI joint development at birth:

Joints undeveloped, smooth, flat, glides in any direction. Stability provided by ligaments. Begins to develop during walking.

15

SI joint development during teenage years:

Roughening of surfaces, development of grooves and ridges. Male more pronounced than female.

16

SI joint development during 20s and 30s:

Articulate changes are well established. Joint surfaces become more irregular. Iliac tuberosity gets bigger. Joint surface erosions begin.

17

SI joint development during 40s and 50s:

Each individual SI joint is unique to varying degrees (more in males)

18

SI joint in the 20s and beyond, this possible issue on iliac surface:

Osteoarthritis (DJD)

19

In 40s and 50s, possibililty of developing these issues in your SI joint:

Joint adhesions, osteophytes, fusion

20

60s and beyond, SI joints have a high prevalence of:

Bony ankylosis (fusion)

21

What is bony ankylosis?

Fusion

22

Bony ankylosis is gender dependent (percentages)

Male 27.7% and Female 2.3%

23

Bony ankylosis is age dependent in men (percentages)

  • 20-39 years 5.8%
  • 60-79 years 31.1%
  • Over 80 years 46.7%

24

Fusion occurs mainly in this part of the SI Joint

Superior part

25

Major STATIC function of the pelvis:

Bear trunk weight

26

What is the posterior arch of the pelvis?

Q image thumb

2 pillars of bone running through SI and acetabular fossa

27

Which arch is the major weight bearer of the pelvis?

Posterior arch

28

Name the 2 gravitational forces acting on the posterior arch:

  1. Down and posterior, weight resisted by wedge-shaped sacrum
  2. Down and anterior, weight resisted by “S” shaped joint, posterior ligaments, interosseous ligaments, sacrotuberous ligaments

29

What is the anterior arch of the pelvis?

Pubic rami connects posterior arches and acts as a compression strut

30

Self-locking mechanism of the SI joint is called:

Form closure

31

What is form closure?

  • Wedge shape of sacrum
  • Interlocking groove (sacrum) and ridge (ilium)
  • S-shaped joint surfaces

32

What is force closure?

Tension in muscles, ligaments and thoracolumbar fascia aids in stabilizing the SI joints

33

Force closure in the pelvis:

Creates lateral to medial pressure from ilia to the sacrum which compresses the SI joints

34

Research finds the average ROM for total flexion and extension in the SI is:

1-8˚

35

Describe Sacral Nutation and Counternutation in terms of sacral base movements and lumbosacral extension/flexion

Q image thumb

Nutation: Sacral base moves anterior and inferior (lumbosacral extension)

Counternutation: Sacral base moves posterior and superior (lumbosacral flexion)

36

When the lumbosacral region extends, the sacrum:

Nutates

37

When the lumbosacral region flexes, the sacrum

Counternutates

38

During pregnancy there is _________ pelvic joint mobility

Increased (2.5 times)

39

During delivery, the sacrum

Counternutates and nutates

40

When you inhale, your sacrum

Counternutates

41

When you exhale, sacrum

Nutates

42

In flexion, PSIS moves ____ and ___ and in extension, PSIS moves ____ and ___

Q image thumb

Flexion: posterior and inferior

Extension: anterior and superior

43

SI joint motion is named according to __________ movement relative to the _________, NO MATTER what bone moves.

Ilium; sacrum

44

Is this flexion or extension of the SI joint: ilium flexes relative to the sacrum

Flexion

45

Is this flexion or extension of the SI joint: the sacrum nutates relative to the ilium

Flexion

46

Is this flexion or extension of the SI joint: ilium extends relative to the sacrum

Extension

47

Is this flexion or extension of the SI joint: the sacrum counternutates relative to the ilium

Extension

48

If PSIS go away from midline: 

Q image thumb

exteternal rotation

49

If PSIS go toward midline: 

Q image thumb

internal rotation