Surg Radiol Anat (2009) 31:419–423 DOI 10.1007/s00276-009-0460-8 123 ORIGINAL ARTICLE Connection types between the spinal root of the accessory nerve and the posterior roots of the C2–C6 spinal nerves Canan Y. Saylam · Mustafa Orhan · Z. Asl Aktan Ikiz · Hülya Uçerler · Mehmet Zileli Received: 9 September 2008 / Accepted: 31 December 2008 / Published online: 4 February 2009 © Springer-Verlag 2009 Abstract Purpose The aim of this study was to demonstrate the connection types and frequency between the accessory nerve and the posterior roots of the C2–C6 cervical nerves. Methods The cranial cervical regions of 49 specimens from 27 human cadavers were used for the present study under an operating microscope. Results Five diVerent connection types between the accessory nerve and the posterior roots of the cervical nerves were recorded and photographed (types A–F). One of these types was not described previously in literature (type F). All connections between the posterior roots of the C2–C6 spinal nerves and the accessory nerve were at the level of the C2 segment. Type B was the most frequently seen type in our series. One of the rootlets of the cervical posterior root joined the accessory nerve without a connec- tion to the spinal cord in type B. Conclusions The clinical importance of these connections is especially noticed during the radical neck dissection as it may lead to the development of the shoulder-arm syndrome. Keywords Accessory nerve · Posterior root of the cervical nerve · C2 spinal nerve · Trapezius · Shoulder syndrome · Radical neck dissection Introduction The spinal root of the accessory nerve arises from a motor nucleus which extends from the junction of the spinal cord and medulla to the sixth cervical segment classically. Some root- lets emerge directly, others run cranially before exiting [6]. The most disabling side eVect of radical neck dissection is the shoulder syndrome that comprises atrophy of the tra- pezius muscle, subluxation in the sternoclavicular joint, rotation of the scapula, inability to abduct the horizontal level and pain [1, 2]. The shoulder syndrome following the standard radical neck dissection for head and neck tumors is seen in some of the patients due to the paralysis of the trapezius because of sacriWcing the accessory nerve. The post-surgical variable clinical picture such as normal func- tion or incomplete denervation of the trapezius in other patients was explained by the innervation of this muscle by cervical nerves, independent of the spinal accessory nerve [3, 4, 6, 7]. The aim of this study was to demonstrate the connection types and frequency between the accessory nerve and the posterior roots of the C2–C6 cervical nerves. Materials and methods The cranial cervical regions of 49 specimens from 27 for- malin Wxed (10%) human cadavers (25 male and 2 female) were examined under an operating microscope (Möller-Wedel Spectra, Germany) in Ege University Department of Anatomy. Only the right sides could be used in two cadavers, and only the left sides could be used in three cadavers. Both sides were observed in 22 cadav- ers. The skin on the nuchal region, adipose tissue and the nuchal muscles was removed. The arches of the cervical C. Y. Saylam (&) · M. Orhan · Z. A. Aktan Ikiz · H. Uçerler Department of Anatomy, Faculty of Medicine, Ege University, 35100 Bornova, Izmir, Turkey e-mail: canan.y.saylam@ege.edu.tr M. Zileli Department of Neurosurgery, Ege University, Izmir, Turkey