The PSIS test is a physical examination maneuver used by therapists to assess the movement of the posterior superior iliac spines (PSIS) during trunk flexion.
How is the PSIS Test Performed?
The PSIS test is conducted with the patient in a standing position. The therapist will perform the following steps:
- Locate the PSIS: The therapist first locates the PSIS on both sides of the patient's lower back.
- Thumb Placement: The therapist places their thumbs directly on each PSIS.
- Trunk Flexion: The patient is then instructed to bend forward as far as they comfortably can, flexing at the trunk.
- Observe Movement: The therapist closely observes the movement of the PSIS during the forward bend, noting if the movement was symmetrical or asymmetrical.
Interpreting the Results
The results of the PSIS test are interpreted as follows:
- Negative Test: If both PSIS move symmetrically (or evenly) in a cephalic (towards the head) and/or ventral (towards the front) direction during trunk flexion, the test is considered negative. This indicates that the movement between the two sides is balanced.
- Positive Test: If one PSIS moves more than the other in the cephalic and/or ventral direction during trunk flexion, the test is considered positive. This asymmetry suggests that one side of the pelvis is not moving as freely as the other.
What Does a Positive PSIS Test Indicate?
A positive PSIS test suggests potential biomechanical dysfunctions or restrictions within the pelvic region. This may indicate the following:
- Sacroiliac Joint (SIJ) Dysfunction: A common finding associated with a positive PSIS test is a restriction or altered movement pattern at the SIJ on the side that is not moving as freely during flexion.
- Muscle Imbalances: Imbalances in muscles surrounding the pelvis and spine may contribute to altered movement patterns, leading to an asymmetrical movement of the PSIS.
- Other Soft Tissue Restrictions: Restrictions in ligaments or other soft tissues around the pelvis and lower back can also cause asymmetrical movement patterns during trunk flexion.
Example
For example, if during the test, the right PSIS moves further upward (cephalic direction) and more forward (ventral direction) compared to the left PSIS when the patient bends forward, the test would be considered positive on the right side. This suggests that there might be an issue with the mobility of the right SIJ or related soft tissues.
| Test Result | Description |
|---|---|
| Negative | Symmetrical movement of both PSIS in the cephalic and/or ventral direction during trunk flexion. |
| Positive | Asymmetrical movement with one PSIS moving more than the other in the cephalic and/or ventral direction during trunk flexion. |
