The developing understanding of the morphology of the cervical spine has revealed the complexity of the system. A review of selected literature reported that a number of the joints have an unusual nature and exhibit complicated and even paradoxical motions. For the practicing therapist, the significance of these observations is that assessment and treatment procedures of the cervical spine must be very carefully analyzed. There are significant differing behaviors of some of the cervical joints in response to small changes in movement patterns or initial positioning. Therefore it is not possible to broadly classify results of assessment procedures as normal or pathological without a clear and detailed understanding of the underlying morphology.