Table 1: The Sternal Instability Scale (SIS).
# special testing includes shoulder flexion (unilateral/bilateral), trunk lateral flexion or rotation, coughing and opposing movements of the upper limbs (e.g. flexion, abduction and external rotation of one upper limb accompanied by extension, adduction and internal rotation of the other upper limb).
| Grades of Motion | Sternal Instability Scale |
| 0 | Clinically stable sternum (no detectable motion) - normal |
| 1 | Minimally separated sternum (slight increase in motion upon special testing# - upper limbs, trunk) |
| 2 | Partially separated sternum- regional (moderate increase in motion upon special testing#) |
| 3 | Completely separated sternum- entire length (marked increase in motion upon special testing#) |