Sacrum and Innominates

Question 1

What is often the first ligament to become painful in lumbosacral decompensation?

Answer 1

iliolumbar

Question 2

What ligament divides the greater and lesser sciatic foramen

Answer 2

Sacrospinous

Question 3

origin of piriformis

Answer 3

inferior anterior aspect of the sacrum

Question 4

Insertion of piriformis

Answer 4

greater trochanter of femur

Question 5

Action of piriformis

Answer 5

-Externally rotates, extends thigh and abducts thigh with hip flexed

Question 6

Innervation of piriformis

Answer 6

S1 and S2 nerve roots

Question 7

Clinical importance of piriformis

Answer 7

• About 11% of the population will have either the entire or peroneal portion of the sciatic nerve running through the belly of the piriformis
• Therefore, piriformis hypertonicity can cause buttock pain that radiates down the thigh, but not usually below the knee

Question 8

Describe the respiratory motion of the sacrum

Answer 8

• Occurs about SUPERIOR transverse axis
• located approximately at S2
• During inhalation, the sacral base will move posterior
• During exhalation, the sacral base will move anterior

Question 9

Describe the Craniosacral motion of the sacrum

Answer 9

• Motion occurs about the SUPERIOR transverse axis
• During craniosacral flexion, the sacral base rotates posteriorly or counternutates
• During craniosacral extension, the sacral base rotates anteriorly or nutates

Question 10

Describe the postural motion of the sacrum

Answer 10

• Motion occurs about the MIDDLE transverse axis of the sacrum
• As a person begins to bend forward, the sacral base moves anteriorly
• At terminal flexion, the sacrotuberous ligaments become taut and the sacral base will move posteriorly

Question 11

Describe the Dynamic motion of the sacrum

Answer 11

• Motion that occurs during ambulation
• As weight bearing shifts from one side to the other while walking, the sacrum engages two sacral oblique axis
• Weight bearing on the left leg (stepping forward with the right leg) will cause a left sacral axis to be engaged
• left on left to right on right

Question 12

Innominate rotation occurs around what axis

Answer 12

inferior transverse axis

Question 13

etiology of superior pubic shear

Answer 13

trauma or a tight rectus abdominus muscle

Question 14

Etiology of inferior pubic shear

Answer 14

trauma or tight adductors

Question 15

What is another name for a unilteral sacral flexion or extension?

Answer 15

sacral shear

Question 16

What are the sacral torsion rules

Answer 16

• When L5 is sidebent, a sacral oblique axis is engaged on the same side as the sidebending
• When L5 is rotated, the sacrum rotates the opposite way on an oblique axis
• the seated flexion test is found on the opposite side of the oblique axis

Question 17

Due to birth mechanics, what is a common sacral dysfunction in the post-partum patients

Answer 17

bilateral sacral flexion

Question 18

What axis do bilateral sacral flexions/extension rotates around

Answer 18

Middle transverse axis

Question 19

Describe how psoas syndrome affects lumbars

Answer 19

-L1 and L2 will be flexed, sidebent, and rotated to SAME SIDE of contracture