Several terms apply to pain of cervical origin. These include radiculopathy, radicular pain or brachialgia, neck pain, and somatic referred pain. In the past and to some extent still, these terms have been confused, and sometimes used wrongly as equivalent and referring to the same phenomenon. The conditions or symptoms to which these terms refer differ in mechanism and cause; they differ with respect to the investigations required and the treatment that is appropriate. It is important, therefore, not just for taxonomic purposes (Merskey & Bogduk, 1994) but also for clinical purposes, to define how the terms should correctly be used.

Radiculopathy is a condition in which conduction along peripheral nerves is blocked at the level of the spinal nerve or its roots (Merskey & Bogduk, 1994). It is manifest clinically as numbness and/or weakness in a segmental distribution. Reflexes may be impaired according to whether conduction is blocked in Ia afferents or motor efferents or both. Paresthesiae may be another feature, and are indicative of the spinal nerve or its roots becoming ischemic. In essence, radiculopathy is a classical neurological disorder, manifest by objective neurological signs in a segmental distribution. Although pain may be an accompanying feature, it is not a necessary criterion. The diagnosis of radiculopathy is based on the objective neurological signs.

Radicular pain is pain arising from a disorder of a spinal nerve or nerve root (Merskey & Bogduk, 1994). It is perceived in the distribution of that nerve. Accordingly, cervical radicular pain is perceived in the upper limb. For that reason cervical radicular pain is not neck pain. Although neck pain may be a small component of radicular pain, radicular pain is never perceived exclusively in the neck. Its cardinal distribution is in the arm and forearm. Radicular pain may occur in association with radiculopathy, and for that reason it has been customary to group the two into one entity. Doing so, however, creates misconceptions, fornot all pain that is associated with radiculopathy is necessarily radicular pain; radicular pain can occur without features of radiculopathy; and radiculopathy can occur without pain.

Neck pain is pain perceived in the cervical region of the spine, i.e. anywhere in the region bounded superiorly by the superior nuchal line, inferiorly by an imaginary transverse line through the T1 spinous process, and laterally by the margins of the posterior cervical muscles (Merskey & Bogduk, 1994).