Sacroiliac Joint

Question 1

the iliac joint surfaces are made up of:

Answer 1

fibrocartilage

Question 2

the sacral joint surfaces are made up of:

Answer 2

hyaline cartilage

3-5x thicker than fibrocartilage

Question 3

What type of joint is the SI joint

Answer 3

a synovial articulation or diarthrosis

Question 4

Anterior sacral ligament

Answer 4

an anterior inferior thickening of the fibrous capsule
relatively weak compared to the rest of the SI ligaments
extends between the anterior inferior borders of the iliac auricular surface and anterior border of the sacral auricular surface

Question 5

Interosseous Ligament

Answer 5

a short ligament located deep to the dorsal SI ligament

forms the major connection between the sacrum and the innominate

Question 6

Dorsal SI ligament

Answer 6

tough strong ligament
connects PSIS with lateral crest at S3/S4
made slack with nutation and taught with counternutation

Question 7

Sacrospinous Ligament

Answer 7

three large fibrous bands
stabilizes against nutation
counteracts against the dorsal and cranial migration of the sacral apex during weight bearing

Question 8

Sacrotuberous Ligament

Answer 8

extends from the ischial tuberosity to the lateral margin of the ilium, sacrum, and coccyx
counteracts nutation of the sacrum

Question 9

Pubic symphysis

Answer 9

no synovial tissue, contains a fibrocartilaginous disc

bone surfaces of this joint are covered with hyaline cartilage but kept apart by the disc

Question 10

How many muscles attach to the sacrum and/or innominate?

Answer 10

35

primarily stabilize the SI joint rather than move it

Question 11

Piriformis

Answer 11

primarily functions to produce external rotation and abduction of the femur
also thought to function as an internal rotator and abductor of the hip when flexed beyond 90 deg.

Question 12

Pelvic Floor Muscles include:

Answer 12

Levator ani group:
pubococcygeus, puborectalis, and iliococcygeus
and the coccygeus muscle

Question 13

Function of pelvic floor muscles

Answer 13

work in a coordinated manner to increase intra-abdominal pressure, provide rectal support, inhibit bladder activity, help support pelvic organs, and assist in lumbopelvic stability

Question 14

Innervation of the anterior portion of the SI joint

Answer 14

posterior rami of L2-S2 roots

highly variable and may differ among individuals

Question 15

Chiropractic Model of SI biomechanics

Answer 15

as one innominate flexes, the ipsilateral sacral base moves anterior and inferior and as the other innominate extends, the sacral base on that side moves posterior and superior

Question 16

Osteopathic model of SI biomechanics

Answer 16

the sacrum rotates around two oblique axes

the innominates are capable of rotating anteriorly and posterior

Question 17

SI joint Stress tests

Answer 17

Gaenslen’s
Lewin Gaenslen’s
Hibb
Fabere

Question 18

SI joint stress tests are designed to:

Answer 18

assess the integrity of the joint and surrounding ligaments

believed to be sensitive for severe arthritis or ventral ligament tears