What is the technique used to assess the spinal accessory nerve?

The technique involves assessing the spinal accessory nerve by having the patient shrug their shoulders while simultaneously resisting head movement. This nerve primarily controls the sternocleidomastoid and trapezius muscles, which are responsible for turning the head and elevating the shoulders. When asking the patient to perform these actions, you can effectively evaluate the strength of the muscle innervated by the spinal accessory nerve and determine if there are any issues with nerve function.

Observing the patient as they breathe and asking them to blink and smile or say a specific phrase are techniques associated with other cranial nerves and not specifically for assessing the spinal accessory nerve. These actions do not uniquely evaluate the nerve that controls shoulder shrugging and head rotation, which makes the correct technique distinctly focused on the capabilities of the trapezius and sternocleidomastoid muscles.