In Seok Han, Young Eun Kim* and Sunghwan Jung
The Journal of Mechanical Science and Technology, vol. 26, no. 6, pp.1857-1864, 2012

Abstract : The cervical intervertebral disc has a unique feature in that a fissure or cleft runs along the uncinate process toward the nucleus pulposus called the uncovertebral joint. A three-dimensional finite element model for the multi-level cervical spine is developed for the purpose of investigating the biomechanical significance of the uncovertebral joints. The original disc model is modified to simulate the absence of the uncovertebral joints (UJRM) by replacing the fissures with continuous annulus fibrosus. The absence of the uncovertebral joints results in decreased motion in all loading modes and C3/C5 segment is most affected. The differences (normalized by the results from the original disc model) between the original disc model and UJRM in rotation are -3.9, -6.1, -14.0 and -24.4% for 1Nm of flexion, extension, axial rotation and lateral bending moment, respectively. The uncovertebral joint tends to increase the coupled motion in lateral bending motion, but the coupled motion difference varies depending on the level of motion segment in axial rotational motion. Data derived in this analysis can help promote improvement of designing total disc replacement devices.

Keyword : Uncovertebral joints; Cervical spine; Finite element model; Range of motion