Looking to understand lumbar-pelvic-hip movement?

Hello, PT student here:

Have been reviewing the Anatomic-Biomechanical Model of the sacrum.

The text I am referencing has limited images and the explanation of this subject is a little confusing when discussing lumbar-pelvic-hip movement. Below is paragraph from the text. I am not sure what the last sentence means.

"Foward bending. Sacral flexion, or nutation, involves an anterior rotation in the sagittal plane, so that the anterior aspect of the sacrum inclines downward. If this sacral flexion occurs from top to bottom (as part of lumbar flexion), it results in flexion (nutation) of the sacrum. However if the sacral flexion occurs from bottom to top (as part of a posterior pelvic tilt or hip flexion), the sacrum extends (counternutates)"

In addition, I would be most appreciative if someone has a simplistic way of communicating the theoretical movements of lumbar-pelvic-hip in forward bending (from top to bottom/bottom to top), backward bending, side bending, trunk rotation.

Regards,

M

Lumbopelvic biomechanics can become quite confusing. I suggest picking up the following books: Philip Greenman, "Manual Medicine" Sharon Wiselfish "IMT for Biomechanics" and Diane Lee, "The Pelvic Girdle"

All are great resources. Good Luck!

Hi,
Iagree with the above post.To understand the movements occuring in the joint complex there is a need for imagination while going through the books mentioned.
I will suggest you to use a method which helped me.Take a square card and hold the card with your index fingers on the middle of lateral borders.Imagine that the upper border is the sacral base,Index fingers are on the inferior lateral angles.Then try to follow the movement of sacrum in card while reading various movements.