This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Upper limb, Subject name: Anatomy
A 43 year old woman came with a large abscess in the middle of the right posterior triangle of the neck. The physician incised and drained the abscess. Five days later the patient noticed that she could not extend her right hand above her head to brush her hair. What is the cause 
Select and explain. 
A. Damage to scalenus medius, B. Injury to suprascapular nerve, C. Cut to spinal pa of accessory nerve, D. Spread of infection to shoulder joint
C: Cut to spinal pa of accessory nerve
Answer: C: Cut to spinal pa of accessory nerve 
Explanation: Spinal accessory nerveThe damages to spinal accessory nerve damage the trapezius muscle that leads to loss of hyperabduction of arm.reference- Clinical Anatomy for students, a problem-solving approach, Neeta v Kulkarni, 2nd edition, page no.463