Pelvis rotation and tilt

The skeleton of the pelvis is a basin-shaped ring of bones connecting the vertebral column to the femora.

Its primary functions are to bear the weight of the upper body when sitting and standing, transferring that weight from the axial skeleton to the lower appendicular skeleton when standing and walking, and providing attachments for and withstanding the forces of the powerful muscles of locomotion and posture. Compared to the shoulder girdle, the pelvic girdle is thus strong and rigid.

Source NHS Choices

Observations