Fig. 1.

Dorsal spinal cord showing path of spinal accessory nerve (SAN) from its rootlets to the jugular foramen. Posterior inferior cerebellar artery (PICA) emerges between SAN and vagus nerve. Cere cerebellum, CNVII/VIII facial-vestibulocochlear nerve complex, CNIX glossopharyngeal nerve, CNX vagus nerve, CRs cranial roots of accessory nerve, DL denticulate ligament, DSR dorsal spinal rootlets, Dura and Arach dura and arachnoid mater, JF jugular foramen, PICA posterior inferior cerebellar artery, PSA posterior spinal artery. SAN spinal accessory nerve, SANr spinal accessory nerve rootlets, VA vertebral artery, IVth fourth ventricle