100 dissections performed in the Anatomy Laboratory have made it possible to clarify certain details relating to the cervical trajectory of the accessory nerve (traditionally called the 11th or spinal nerve), its relationship with the jugular vein, with the S.C.M. muscle, its position on the anterior and posterior edges of the S.C.M. and on the anterior edge of the trapezius muscle, and the frequency of its branching in the sub-clavicular fossa.