Sacroiliac Joint

Question 0

How much mobility is available in the SIJ?

Answer 0

1-2mm of rotation with some movements

Question 1

What is the function of the SIJ?

Answer 1

Stable and mobile joint: stability to transmit forces from the spine to the LE and mobile to absorb forces

Question 2

What is the SIJ comprised of?

Answer 2

Hyaline cartilage - allows movement but cannot heal itself

Question 3

What are the two structures of the SIJ?

Answer 3

Sacrum and the ilia

Question 4

What is the structure of the sacrum?

Answer 4

Posterior syndesmosis and anterior synovial joint

Question 5

What does the posterior syndesmosis of the sacrum articulate with?

Answer 5

Ilium

Question 6

What are factors of the anterior synovial joint of the sacrum?

Answer 6

S1-S3, multiplanar, curvy, and comprised of hyaline cartilage

Question 7

What does the ilia articulate with?

Answer 7

Tuberosity of the sacrum

Question 8

Is there a lot of dynamic support in the SIJ?

Answer 8

No

Question 9

What is the shape of the sacrum?

Answer 9

Wedge shaped - pushed down as weight comes down through the spine which provides stability

Question 10

What ligaments support the SIJ?

Answer 10

1. Iliolumbar ligament
2. Anterior sacroiliac ligament
3. Long posterior (dorsal) ligament
4. Sacrospinous ligament
5. Sacrotuberous ligament
6. Interosseous ligaments
7. Superior, inferior and posterior ligament

Question 11

What is the function of the anterior sacroiliac ligament?

Answer 11

Provides compression and prevents the pelvis from outflaring (stretched with outflaring)

**Not able to palpate

Question 12

Where does the long posterior (dorsal) ligament attach?

Answer 12

Attaches superiorly to the PSIS and inferiorly to the fascia and the sacrum

Question 14

What is the function of the longer posterior (dorsal) ligament?

Answer 14

Checks counternutation

Question 15

What is the function of the sacrospinous ligament?

Answer 15

Checks nutation - ligaments would be stretched with posterior rotation of the innominate (nutation)

Question 16

Where does the sacrotuberous ligament attach?

Answer 16

Ischial tuberosity and the PSIS, sacrum, and coccyx

Question 17

What is the function of the sacrotuberous ligament?

Answer 17

Checks nutation

Question 18

What is the interosseous ligament and what is its function?

Answer 18

Major bond between the ilia and sacrum - aids in stability and compression

Question 19

What are the three ligaments around the pubic symphysis and what are their functions?

Answer 19

1. Superior ligament - supports superiorly
2. Inferior ligament - supports inferiorly
3. Posterior ligament - supports posteriorly

Question 20

What are the four muscles that provide anterior support of the pubic symphysis?

Answer 20

1. Transverse abdominus
2. Rectus abdominus
3. Internal obliques
4. Adductor longus

**RA and TA provide support diagonally and cross with the AL

Question 21

What muscles posteriorly rotate the pelvis?

Answer 21

Gluts and hamstrings

Question 22

What muscles anteriorly rotate the pelvis?

Answer 22

Hip flexors

Question 23

What muscles provide posterior support?

Answer 23

1. Thoracolumbar fascia
2. Glut max
3. IT band
4. Erector spinae

Question 24

What is the only muscle that crosses the SIJ?

Answer 24

Piriformis

Question 25

What are symmetrical innominate movements?

Answer 25

Anterior and posterior tilt

Question 26

What are asymmetrical innominate movements?

Answer 26

1. Pelvic torsion - one side moves anteriorly and one side moves posteriorly 2. Anterior/posterior rotation 3. Inflare/outflare 4. Upslip/downslip **Movement of innominate on the sacrum

Question 27

How much movement is allowed by the SIJ?

Answer 27

1.5mm - small movements

Question 28

What is anterior rotation?

Answer 28

Anterior tilt of one side

Question 29

What is posterior rotation?

Answer 29

Posterior tilt of one side

Question 30

What is inflare?

Answer 30

Internal rotation of one side (joint space by PSIS gets bigger)

Question 31

What is outflare?

Answer 31

External rotation of one side (joint space by PSIS gets smaller)

Question 32

What is upslip?

Answer 32

Sliding up on one side

Question 33

What is downslip?

Answer 33

One side slides down

Question 34

How does the ASIS move with anterior and posterior movements?

Answer 34

Anterior movement of innominate - ASIS moves inferiorly | Posterior movement of innominate - ASIS moves superiorly

Question 35

What are the two sacral movements?

Answer 35

Nutation and counternutation

Question 36

What is sacral nutation?

Answer 36

Sacral base moves anteriorly and coccyx moves posteriorly - think FLEXION

Question 37

What is sacral counternutation?

Answer 37

Sacral base moves posteriorly and coccyx moves anteriorly - think EXTENSION

Question 38

Describe forward bending with regards to sacral movement.

Answer 38

``` 0-60* = sacral nutation >60* = sacral counternutation ```

Question 39

Describe hip flexion with regards to sacral movement.

Answer 39

Pelvis rotates posteriorly and sacrum counternutates

Question 40

Describe backward bending with regards to sacral movement.

Answer 40

Pelvis rotates posteriorly and sacrum nutates

Question 41

What occurs during standing?

Answer 41

Anterior rotation of the innominate

Question 42

Where does the sacrospinous ligament attach?

Answer 42

Ischial spine and the sacrum/coccyx - joins with the long posterior (dorsal) ligament to attach to the PSIS

Question 43

What ligament limits sacrum rotation?

Answer 43

Sacrospinous ligament