The lesion of the accessory spinal nerve is often of iatrogenic origin. We report the case of an injury after a right jugulocarotid lymph node biopsy. A 30-year-old patient was referred for the treatment of right cervical lymphadenopathy suspected of tuberculosis. After the intervention and confirmation of tuberculosis diagnosis, the patient presented a functional impotence of the right shoulder and swarming of the right hand. The clinical examination found an active limitation of the shoulder, and a wasting of the upper bundle of the right trapezius muscle and the sternocleidomastoid. The EMG showed axonotmesis of the accessory spinal nerve and the MRI an amyotrophy of the trapezius with denervation edema. A simple rehabilitation has been scheduled. Damage of the accessory spinal nerve most often occurs after local surgery. EMG is essential for diagnosis. Rehabilitation is the first therapeutic option. Surgery can be considered if it fails. The surgeons must consider the protection of the accessory spinal nerve in case of cervical lymph node surgery.