Final answer:
When you shrug your shoulders, the scapulae undergo elevation. This is the primary movement for shrugging, as depression occurs when you lower your shoulders from an elevated position.
Step-by-step explanation:
The movements that occur at the scapulae when you shrug your shoulders are elevation and depression. Elevation is the upward movement of the scapula and shoulder, which is the primary action during shoulder shrugging. Depression is the downward movement, but this is not typically involved in the action of shrugging your shoulders unless you are actively lowering them from an elevated position.