ABSTRACT
The spinal accessory nerve (cranial XI nerve) can be compressed at multiple sites along its course from the base of the skull, along the lateral side of the neck, and to its termination in the region of the trapezius muscle. Nerve compression alters the function of the sternocleidomastoideus muscle and the trapezius muscle. Impaired muscle function alters scapular alignment, resulting in a more prominent inferior scapular tip. Patients present with weak shoulder elevation, scapular instability, and a decreased ability to smoothly elevate the arm.
