part of part of in taxon results in morphogenesis of anatomical structure morphogenesis accessory nerve development cranial nerve morphogenesis accessory nerve morphogenesis CN XI morphogenesis The process in which the anatomical structure of the accessory nerve is generated and organized. The spinal branch of this motor nerve innervates the trapezius and the sternocleidomastoid muscles. The cranial branch joins the vagus nerve and innervates the same targets as the vagus nerve. GO:0021607 Tetrapoda accessory XI nerve