The uncinate processes (uncinate processes or processus uncinati) are paired bony lips projecting superiorly from the lateral margins of the C3-C7 vertebral body superior end plate. They articulate with the lateral bevelled edge of the vertebral body above to form the uncovertebral joints of Luschka (neurocentral joints), which are amphiarthroses rather than true synovial joints. The uncinate processes form the anteromedial boundary of the intervertebral foramen.
Uncinate osteophytes from degeneration of the uncovertebral joints are the single most common cause of cervical radiculopathy from foraminal stenosis. The osteophyte grows posterolaterally to compress the exiting nerve root in the foramen. Anterior cervical discectomy and fusion (ACDF) includes uncinectomy (removal of the uncinate process) to decompress the foramen laterally. Posterior cervical foraminotomy approaches the foramen from the posterior and removes the medial facet and lateral uncinate without disturbing the disc. The uncinate process must be identified before any drilling in this area to protect the adjacent vertebral artery.
Degenerative osteophyte formation at the uncovertebral joint of Luschka extends the uncinate process posterolaterally into the neural foramen, compressing the exiting cervical nerve root and producing dermatomal arm pain; ACDF with uncinectomy removes the osteophyte under direct vision from the anterior approach to decompress the foramen.
