The spinal accessory nerve (SAN) within the posterior triangle (PT) is the commonly injured nerve in the body. Recognizable landmarks to locate this nerve in PT may help the surgeon in identifying it for repair, use of it in peripheral nerve neurotisation, or avoiding it as in proximal brachial plexus repair. The present study was undertaken to offer reliable superficial landmarks for the identification of the SAN within the PT. Material and methods: The neck was dissected in 16 foetal cadavers (total 32 PT). The foetuses were divided into 2 groups depending upon their age- group 1 (13-24 weeks) and group 2 (24-38 weeks). Morphometric studies in terms of distances and angles were conducted in both groups on the SAN and its anatomical surrounding landmarks. Results: The mean of all the parameters which we have measured in both groups of foetuses to locate the SAN is given in the tables in results. Mean angle which the SAN makes after exiting from SCM in group 1 and group 2 on right and left side is 73.3° and 60.5°,65° and 57.1° . Mean angle which the SAN makes before its entry into trapezius in group 1 and group 2 on right and left side is 41.4° and 62.2°, 41.4°and 66.4°. Conclusion: The exact localization of the spinal root of the accessory nerve within the posterior triangle of the neck will help surgeons to avoid its injury while performing surgery at this site.