- Jerk Test is used to test for Posterior Instability
- have the patient sit straight up with the arm forward elevated to 90 degrees and internally rotated to 90 degrees.
- Apply an axial load to the humerus to push it posteriorly.
- positive if there is a ‘clunk’ or pain with the maneuver
- Sensitivity: 73 %
- Specificity: 98%