XI Spinal Accessory Nerve
The spinal accessory supplies the trapezius and sternocleidomastoid muscles.

Examination Technique:

• observe for atrophy or asymmetry of the muscles.
  
  
• observe for quickness of shoulder shrug and ask the patient to shrug their shoulders against resistance.
  
  
• ask the patient to turn their head to the opposite side against resistance, both watch and palpate the sternocleidomastoid muscle.
  
  
• ask the patient to flex their head forward against resistance, placing your opposite hand against the back of the head gently to support the patient’s neck should there be any weakness.