This study was performed to assess the prevalence of signs and symptoms related to cervical spine disorders (CSD) in subgroups of patients with temporomandibular disorders (TMD) and to compare TMD patients and CSD patients with regard to the results of orthopaedic cervical spine tests. One hundred and eleven consecutive patients with TMD and 103 consecutive patients with signs and symptoms of CSD were examined. The results indicated that there is a considerable overlap in the signs and symptoms of patients with TMD and patients with CSD. Signs and symptoms on neck extension occurred more often in CSD patients than in subgroups of TMD patients. No significant differences in upper cervical extension, neck flexion, and shoulder girdle function were found between CSD patients and subgroups of patients with TMD. Patients with CSD reported neck pain during active and passive movements of the neck more often than the subgroups of patients with TMD. TMD patients and CSD patients did not differ with regard to pain on shoulder girdle function and palpation of the shoulder girdle. Logistic regression analyses showed that orthopaedic tests of the cervical spine are of minor importance in discriminating between patients with TMD and patients with CSD. It is concluded that TMD with a myogenous involvement in contrast to TMD with only an arthrogenous involvement should no longer be viewed as a local disorder of the stomatognathic system. The upper quarter, including the stomatognathic system, cervical spine, and shoulder girdle, should be evaluated in patients with more complex or persistent symptoms in the head and neck region.