During the standing flexion test for the lumbar spine, what indicates a positive test?

A positive standing flexion test for the lumbar spine is indicated when one of the posterior superior iliac spines (PSIS) moves cranially (upwards) first as the patient bends forward. This suggests asymmetrical motion, which can be indicative of a restriction or dysfunction in the lumbar spine or sacroiliac joints.

In this context, the cranial movement of one PSIS may suggest that there is an issue such as sacroiliac joint dysfunction or an abnormality in the pelvic mechanics. When one side moves before the other, it reflects a lack of coordinated motion that is typically expected when the pelvis and lumbar spine accommodate flexion together.

Other responses may reflect various forms of movement or symmetry, which do not signify the same degree of dysfunction as the presence of one PSIS moving cranially before the other. For instance, if both PSIS do not move or move symmetrically, it may indicate a different type of mechanical issue, but not necessarily the same level of dysfunction that the cranial movement first would imply. Thus, the movement of the PSIS cranially first is a key indicator of dysfunction recognized during this test.