The relationship between the spinal accessory nerve and internal jugular vein is important for modified neck dissection surgery. Therefore, the aim of this review was to investigate variations in this relationship. Through a search of the PubMed, Scopus, Web of Science, LILACS, and SciELO databases, the review authors collected anatomical data for inclusion in a meta-analysis, following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Four relationship patterns were identified and classified: type 1, the nerve lies superficial to the vein; type 2, the nerve lies deep to the vein; type 3, the nerve crosses the branches of the vein; type 4, the nerve splits and its branches pass around the vein.
