Exam 1 - SI joint and axial skeleton muscle and joint interactions

Question 1

describe the sacroiliac joint

Answer 1

junction between auricular surfaces of the sacrum and the ilium

tight fitting for stability

shock absorber with heel contact

Question 2

what is keystone of the pelvic ring

Answer 2

sacrum

Question 3

what motions increases risk of LBP due to the SI joint

Answer 3

falling
stepping in a hole
childbirth
repetitive unilateral torsions
postural abnormalities

Question 4

describe the anterior sacroiliac ligament

Answer 4

thickening of the capsule

Question 5

describe the iliolumbar ligament

Answer 5

stabilizer of lumbosacral joint and SIJ

Question 6

describe the interosseous ligament

Answer 6

fills the gap
strong like a syndesmosis at tib/fib

Question 7

describe the sacrotuberous ligament

Answer 7

blends with biceps femoris
runs from sacrum to ischial tuberosity

Question 8

describe the sacrospinous ligament

Answer 8

runs from the sacrum to ischial spine

Question 9

where can SIJ pain be located in the body

Answer 9

ipsilateral lower lumbar region
medial buttock
PSIS
along short and long SIJ ligaments

Question 10

describe the thoracolumbar fascia

Answer 10

important role in mechanical stability of low back and SIJ

attaches to PSIS

Question 11

where is the throacolumbar fascia the most extensive

Answer 11

in the lower back

anterior, middle, posterior layers of the thoracolumbar fascia surround various muscle groups

Question 12

describe the cartilage and the joint surface of the SIJ on the sacrum side

Answer 12

ear-shaped or L-shaped
vertical short and more horizontal long arm

sacral articular cartilage is normally white and smooth (hyaline)

irregular ridges and depressions are matched with shapes of the illium that allow the sacrum and ilium to interlock

Question 13

how is the articular surface of the sacrum twisted

Answer 13

above downwards
like a propeller

Question 14

describe the cartilage on the SIJ on the ilia side

Answer 14

cartilage is mainly fibrocartilage 1-2 mm thickness

Question 15

describe the sacroiliac joint and the joint capsule

Answer 15

synovial joint

joint capsule is 2 layers
- external fibroblasts and collagen fibers
- inner synovial layers

Question 16

how does the sacroiliac joint change with aging

Answer 16

surface changes from flat in young age to ridges/grooves throughout puberty

Question 17

what is the purpose of the ridges/grooves of the SIJ

Answer 17

develops through puberty
enhances stability

Question 18

describe the osteo- and arthrokinematics of the iliac crests on the sacrum

Answer 18

iliac crest move on the sacrum

innominate motion

Question 19

t/f
movement at the SI joint does not affect movement at the pubic symphysis

Answer 19

false
movement at the SI joint does affect movement at the pubic symphysis

Question 20

describe the osteo- and arthrokinematics of the sacrum on the iliac crest

Answer 20

sacrum moves on innominates

sacroiliac motion

Question 21

describe the osteo- and arthrokinematics of the sacrum on the iliac crest

Answer 21

sacrum moves on innominate

sacroiliac motion

Question 22

what are the investigation methods of the SIJ biomechanics

Answer 22

manipulation during surgery/cadaver

radiographic

imaging after insertion of tantalum balls into innominate and sacrum

inclinometers

computerized analysis

Question 23

what are the NWB motions occurring within the pelvis at the SIJ innominates

Answer 23

10-12 degrees innominate posterior rotation coupled with 6 mm anterior translation

2 degree innominate anterior rotation coupled with 8mm anterior translation

Question 24

what are the WB motion occurring within the pelvis at the SIJ innominates

Answer 24

2.5 degree innominate rotation and 0.5-1.6 mm translation

Question 25

t/f motion at the SIJ occurs during movements of the trunk and extremities

Answer 25

true

Question 26

what side of the sacrum dictates the motion

Answer 26

anterior side

Question 27

t/f movement of the SIJ does not continue throughout life

Answer 27

false movement of the SIJ continues throughout life

Question 28

what are the 3 planes of motion of the sacrum in the SIJ

Answer 28

flexion/extension lateral flexion rotation

Question 29

how many degrees of rotation and translation occurs a the sacrum in the SIJ

Answer 29

1-4 degrees of rotaion 1-2 mm tralslation

Question 30

what position is closed packed position of the sacrum in the SIJ

Answer 30

nutation - standing when loaded

Question 31

what position is open packed position of the sacrum in the SIJ

Answer 31

when supine - unloaded sacrum tents to return to counternutation or less stable

Question 32

what is the anterior/forward motion or nutation

Answer 32

flexion of the sacrum

Question 33

what is posterior/backward motion or counternutation

Answer 33

extension of the sacrum

Question 34

what does nutation mean

Answer 34

nodding

Question 35

bilateral motion of sacrum occurs with what motion of the trunk

Answer 35

forward/backward bending of the trunk

Question 36

unilateral motion of the sacrum occurs with what motion

Answer 36

flexion/extension of the lower extremities

Question 37

describe sacral nutation relative to the innominate

Answer 37

forward motion of the sacral promontory into the pelvis coronal axis anteriorly and inferiorly

Question 38

the sacrum glides __ does the short arm and ___ along the long arm

Answer 38

the sacrum glides inferiorly on the short arm and posteriorly along the long arm

Question 39

what resists motion of the sacrum during nutation

Answer 39

wedge shape of sacrum ridges/depressions in point surface interosseous and sacrotuberous ligaments

Question 40

describe sacral counternutation relative to the innominates

Answer 40

sacral base moves posteriorly and superiorly glides anteriorly along long arm and superiorly up short arm

Question 41

t/f coutnernutation of the sacrum is considered to be more stable than nutation

Answer 41

false counternutation of the sacrum is considered to be less stable than mutation because sacrotuberous and interosseous ligaments are lax

Question 42

what limits motion during counternutation of the sacrum

Answer 42

long dorsal ligament

Question 43

during a forward bend, the sacrum (nutates/counternutates)

Answer 43

counternutates

Question 44

during extension, the sacrum (nutates/counternutates)

Answer 44

nutates

Question 45

during anterior rotation on of the pelvis/innominate, what is the glide at the SIJ

Answer 45

inferoposterior glide

Question 46

during posterior rotation of the pelvise/innominate, what is the glide at the SIJ

Answer 46

anterosuperior glide

Question 47

during walking/gait cycle motion sacral (is/is not) the same as forward/backward bending

Answer 47

is not

Question 48

what happens during unilateral motion of the sacrum

Answer 48

one side nutates with side bend induces mutation

Question 49

what occurs during sacral torsion

Answer 49

coupled motion of rotation and lateral flexion

Question 50

what is the middle axis of the sacrum

Answer 50

nutation (flexion) and counternutation (extension) postural S2

Question 51

What is the vertical axis

Answer 51

Unilateral rotation

Question 52

What are the physiological motions

Answer 52

Anterior motion fixation/nutation L on L R on R

Question 53

What are non-physiological motions

Answer 53

Posterior motion fixation/counternutation L on R R on L

Question 54

Describe the R on R or physiological motions

Answer 54

L sacral anterior nutation/rotation R Occurs around R oblique axis

Question 55

Describe how the sacrum moves during the normal walking cycle

Answer 55

Sacrum moves with left torsion on the left oblique axis Return to neutral Rotate right torsion n the right oblique axis Return to neutral

Question 56

T/f Posterior nutation movement does not appear past neutral in the normal walking cycle

Answer 56

True

Question 57

Physiologic or non? - Same side axi as + forward sit - sphinx sacral sulcus gets more even when in extension - negative spring on L5

Answer 57

Physiologic

Question 58

Physiological or non? - other side axis as + forwar sit - sphinx sacral sulcus will get less even when in extension - + spring on L5

Answer 58

Non-physiologic