Cervical disc herniation is a common disease; it can cause severe radicular pain, numbness, motor weakness and cervical myelopathy. Since MRI-diagnostic has become routinely available, the number of patients receiving surgical treatment for cervical disc herniation has rapidly increased. When surgical treatment is necessary, the gold-standard is anterior microdiscectomy and replacement of the disc, either using iliac bone-graft or substitutes, like carbonfibre cages or PEEK-cages, for instance. Therefore, surgery leads to functional loss at the operated motion segment. Clinically, the loss of one cervical motion segment is well tolerated. However, there is concern to create adjacent segment syndrome, that is accelerated degeneration of the adjacent motion segments due to fusion at the operated level. The aim of our study is to investigate the kinematic profile (COR for flexion/extension and lateral bending) of the lower cervical spine (C4 C7) before and after implantation of 3 different types of cervical disc prostheses (Bryan Disc, Prestige Disc, Discover Disc) and to compare the data with the kinematic profile in asymptomatic healthy subjects.