Anatomy and biomechanics of pelvis and lumbar region

Question 1

What are the two joints of the pelvis?

Answer 1

Lumbosacral joint-L5-S1 facet joints
Pubic Symphysis
Sacro-iliac joint

Question 2

On the SI joint the sacrun is more (convex/concave) and the ilium is more (convex/concave)?

Answer 2

Sacrum-more concave

ilium-more convex

Question 3

What is the axis of motion of the sacrum?

Answer 3

At PSIS (S2)

Question 4

What is sacral nutation?

Answer 4

sacral flexion (occurs with lumbar extension)

Question 5

What is sacral counternutation?

Answer 5

Sacral extension (occurs with lumbar flexion)

Question 6

What is the form closure of the SI joint?

Answer 6

passive stability of SIJ from joint surfaces and ligaments

Question 7

What is force closure?

Answer 7

Dynamic stabiliy from myofascial structures for SIJ/sacrum

Question 8

What does Normal lumbopelvic Rhythm require?

Answer 8

Requires hip, pelvis, and lumbar spine. (In FB 70 degrees of hip flexion requires 40 degrees at the lumbar spine?)

Question 9

What motion does the SI go through during stair ascent? Descent?

Answer 9

posterior rotation motion for ascent

Anterior to neutral for descent