Functional Anatomy and Biomechanics of the Pelvis Flashcards Preview

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Flashcards in Functional Anatomy and Biomechanics of the Pelvis Deck (25)
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1
Q

There are 2 joints in the pelvis. Name and describe them.

A
  1. Lumbosacral joint at L5-S1.
  2. Pubic symphysis, a fibrocartilagenous joint that is critical for stability.
  3. Ilio-sacral joint, part synovial (sacrum), part fibrocartilagneous (ilia); L shape joint
2
Q

In the ilio-sacral joint, which cartilage is thicker: hyaline articular of the sacrum, or fibrocartilage of the ili?

A

Sacral cartilage.

3
Q

Where is the axis of motion for nutation / counter-nutation in the pevlis?

A

S2 @ PSIS

4
Q

In terms of flexion and extension of base relative to the ilium, how would you label nutation and counternutation?

A

NUTATION
-sacral flexion

COUNTERNUTATION

  • sacral extension
  • base of sacram tilts posterior
5
Q

What motion at the lumbar spine is combined with counternutation of the pelvis?

A

The base will be extending, meaning the L-S will FLEX to compensate.

E.g. forward bending

6
Q

Nutation of the pevlis results in ___ of the L-S

A

Extension. E.g. Supine to stand

7
Q

As no muscle act directly on the sacrum, how is movement generated?

A

Trunk creates sacral nutation moment and shear stress.

GRF though LE and hip create posterior sheer force.

8
Q

Form closure describes passive stability and force closure active; what provide these at the pevlis?

A

FORM
-SIJ surfaces and ligaments

FORCE
-myofascial structures for SI

9
Q

What exactly does FORM CLOSURE mean in the pelvis?

A

Form closure describes the stability of the joint from design and anatomy; the sacrum supports the spine and resists forces via high coefficient of friction.

  • wedge thicker superiorly
  • wider anteriorly
  • ridges resist sheer and gliding
  • ligmanetous support aids
10
Q

Form closure is useful at rest, but force closure is needed for mobility. What provides this force closure and what does it mean?

A

Generated by muscles with fiber direction perpedicular to the joint:

POSTERIORLY

  1. Lat dorsi
  2. Glut max

ANTERIORLY

  1. Obliques (pull ilia toward midline)
  2. TrA (pull ilia toward midline)
  3. Rectus

Compressive forces resist shearing of SIJ in combination with ligaments

11
Q

What do the obliques and TrA use as a fulcum to provide stability of pelvis ?

A

Interosseous ligament.

12
Q

The multifidus play a cocontration role with the transversus and pelvis floor muscles. What is it?

A

Stabilize sacrum / SI joint.

13
Q

Which muscles are involved in pelvic girdle control anteriorly, posteriorly and laterally?

A

ANTERIOR
-abdominal fascia, obliques and contralateral adductors

POSTERIOR

  • lat and glut max
  • bicep fem at ischium during gait before intial contact

LATERALLY

  • glut med/min
  • contralateral adductors
14
Q

Name the range of normal lumbopelvic rhythm.

A

In forward bending, 70* hip flexion, 40* lumbar spine.

15
Q

On initial contact on right, the right ilium rotates ___. In midstances, it moves ___, but not past neutral. In preswing, it rotates ___ past neutral.

A

Posterior (via hamstring action)
Anterior (hip ext moment)
Anterior (most hip ext)

16
Q

How doe the pelvis behave during stair climbing?

A

ASCENT
-posterior rotation

DESCENT
-anterior to neutral

17
Q

In gait, pelvic position in ___ during hip flexion and ___ during hip ext.

A

Anterior, posterior

18
Q

How would you test for pelvic dysfunction and list 3 signs/symptoms.

A

TEST

  • active straight leg raise
  • FABER or pelvic compression / distraction
  1. SI displacement
  2. localize pain at jt or ligaments
  3. Pain in sitting or SLS
19
Q

How would you check for abnormal posterior or anterior unilateral rotation, possibly due to a trauma or overuse?

A

Asymmetry of ASIS or PSIS, reduced posterior torsion.

20
Q

Though uncommon, how can ilial upslips and downslips occur?

A

UP
-upward jar to leg

DOWN
-childbirth

21
Q

What are ilial inflares and outflares?

A

IN
-asis on one side closer to midline

OUT
-ASIS further from midline on one side

Likely more related to anterior / posterior torsion

22
Q

What is the likely culprit from an ilial inflare?

A

Anterior / posterior torsion.

23
Q

An upslip or downslip of the pubic ramus is often associated with ___.

A

Ilial torsion.

Downslip could be childbirth.

24
Q

What types of activity can cause Osteitis publis?

A

Kick, running or change in direction activities putting excess strain on symphysis.

25
Q

Diastasis in the pubis can occur post partum and provides significant instability. How many mm is the normal and diastasis gap?

A
Normal = 4-5mm
Diastesis = 13mm

<25mm treated conservatively