Morphometric analysis of the uncinate processes of the cervical vertebrae.

BACKGROUND: Uncinate processes are distinct features unique to cervical vertebrae. They consistently found on posterolateral aspect of the superior end plate of third to seventh cervical vertebrae. In this study, we investigated the morphology of the uncinate processes with a particular emphasis on the regional anatomy and clinical significance.

MATERIALS AND METHODS: The study included 63 vertebrae. The width, height and length of uncinate processes were measured with a digital caliper. We also assessed inclination angle of uncinate process relative to sagittal plane, angle between medial surface of uncinate process and superior surface of vertebra, angle between long axis of the uncinate process and frontal plane, angle between long axis of uncinate process and sagittal plane.

RESULTS: Average width of the uncinate processes ranged from 4.25 mm at C3 to 6.33 mm at T1; average height ranged from 4.88 mm at T1 to 7.54 at C4; and average length ranged from 6.88 mm at T1 to 11.46 mm at C4. We measured the inclination angle of uncinate process relative to sagittal plane, and found it to be relatively constant with T1 having the largest value. The average angle was 41.39°, and the range was 17° to 85°. The angle between the long axis of the uncinate process and the sagittal plane was increasing significantly from C5 to T1. The average angle was 20.74° and the range was 6° to 65°.

CONCLUSIONS: Anatomy of uncinate processes is significant for surgeon who operates on the cervical spine. Hopefully, the information presented herein would decrease complications during surgical approaches to the cervical spine.