Pelvis | SI Joint

Question 1

SI joint: function

Answer 1

Acts as shock absorbers

Question 2

SI Joint:
Open Pack position
Closed Pack position

Answer 2

Open: neutral (the book says counternutation)

Closed: nutation

Question 3

SI Joint:

Type of joint
Normal overall motion

Answer 3

Part synovial (diarthrodial) and part syndesmosis

Slightly moveable, 4-7 Degrees

Question 4

SI Joint:
3 Types of Injury

Answer 4

1. Inflammation/trauma/overuse
2. Hypomobility
3. Instability/Hypermobility

Question 5

SI Joint:
Mechanisms of Injury (4)

Answer 5

1. Sudden jarring (possibly by stepping off of a curb or in a hole)
2. Overzealous kick, missing an object
3. Fall on the buttocks
4. Lift and twist maneuver

Question 6

SI Joint:
Typical Pain pattern (3)

Answer 6

1. Local to the SI
2. Unilateral
3. Can refer to the buttocks and posterior thigh

Question 7

SI Joint:
Painful Movements (3)

Answer 7

1. Sit to stand / transitional movements
2. Turning in bed, getting out of bed
3. Stepping up with a single limb

Question 8

Form Closure

Answer 8

Shape of the anatomy and integrity of the ligaments maintain integrity

Firm closure of this keystone within the two pelvic bones

Question 9

Force Closure

Answer 9

Compression generated by muscles and ligament tension reacting to applied load.

Provides compression to make these forces happen within the SI joint to maintain the sacrum sitting in the pelvis.

Question 10

Ligaments of the Pelvis (4)

Answer 10

1. Long posterior sacroiliac
2. Short posterior sacroiliac
3. Sacrotuberous and sacrospinous
4. Iliolumbar

Question 11

Function:
Long Posterior Sacroiliac ligament

Answer 11

Limits anterior pelvic rotation

Question 12

Function:
Short Posterior Sacroiliac ligament

Answer 12

Limits all motions

Question 13

Function:
Sacrotuberous and Sacrospinous Ligaments

Answer 13

Limits nutation and posterior innominate rotation

Question 14

Function:
Iliolumbar Ligament

Answer 14

Stabilizes the L5 on the ilium

Question 15

Outer Group: Deep longitudinal muscle system (4)

Answer 15

1. Erector Spinae
2. Deep lamina of thoracolumbar fascia
3. Sacrotuberous ligament
4. Biceps femoris

Question 16

Posterior Oblique muscle system (3)

Answer 16

1. Latissimus Dorsi
2. Gluteus Maximus
3. Intervening Thoracolumbar Fascia

Question 17

Anterior Oblique muscle system (3)

Answer 17

1. Internal/External obliques
2. Contralateral adductors of the thigh
3. Intervening anterior abdominal fascia

Question 18

Lateral Muscle System (2)

Answer 18

1. Gluteus Medius and Minimus
2. Contralateral Adductors

Question 19

Inner Muscle system (3)

Answer 19

1. Multifidus
2. Transverse Abdominis
3. Pelvic Floor muscles

Question 20

Muscles involved in a posterior tilt

Answer 20

(See picture)
External oblique muscle
Rectus abdominis muscle

Taut iliofemoral ligament

Gluteus Maximus muscle
Sacrotuberous ligament pulled tight by hamstrings
Hamstring muscles

Question 21

Muscles involved in an anterior tilt

Answer 21

Erector spinae muscle
Iliopsoas muscle
Sartorius muscle
Rectus femoris muscle