A good back support makes it possible to optimize pelvic alignment and then balance the trunk without affecting pelvic alignment. The key to achieving this support goal is in the way the back support pivots around its axis for seat to back angle.

When the Java Back is positioned correctly on the wheelchair, it provides optimal pelvic alignment. It can then be adjusted for trunk balance without changing the pelvic alignment already achieved. Correct height adjustment of the Java Back on the wheelchair is key.
When determining the correct height of the Java Back on the client’s wheelchair, it is important to locate the client’s PSIS (Posterior Superior Iliac Spine).

The PSIS is the most prominent posterior aspect of the iliac crest. If you’re not sure how to locate a client’s PSIS, here are some tips:
- Stand behind the client and find the iliac crest laterally. Move your thumbs in and down until you find a prominent bony bump (which sharply disappears distally and inferiorly).
- Look for the two dimples on the lower back — the PSIS are typically located under the dimples.
Then adjust the back height so that the back angle pivot point lines up with the client’s PSIS. This allows the back to pivot around that point of control at the pelvis and not affect the anterior-posterior (sagittal plain) pelvic orientation.