Center of Rotation Profiles of Lumbar Spine of Healthy Men in Sagittal Plane: A Preliminary Study

BACKGROUND AND OBJECTIVE: Human joint center of rotation (COR) in two dimensional plans is a cinematic variable that can be used for joint assessment, motion analysis, evaluation of treatment and rehabilitation and recognizing abnormalities. The aim of this study was to study COR profiles of lumbar vertebrae and introduce a new method to quantitative expression of COR.METHODS: A total of 22 healthy volunteer males aged between 21-43 years participated in this descriptive study. Variables contained centre of rotation of full, flexion and extension arcs of lumbar vertebral movement. Three radiographies were taken in neutral, full flexion and full extension positions of lumbar spine. The variables were calculated using CARA software after scanning. The descriptive statistics were utilized to description of variables.FINDINGS: The acquired results of full arc COR were in levels of L1 (x=-113, y=107), L2 (x=-74, y=88), L3 (x=-31, y=65), L4 (x=-1, y=37) and L5 (x=12, y=4). The acquired results of flexion arc COR were in levels of L1 (x=-101, y=119), L2 (x=-65, y=97), L3 (x=-26, y=69), L4 (x=2, y=37) and L5 (x=19, y=11). The acquired results of extension arc COR were in levels of L1 (x=-111, y=133), L2 (x=-83, y=111), L3 (x=-36, y=92), L4 (x=25, y=70) and L5 (x=18, y=5). CONCLUSION: According to the results of this study, analysis of motion profiles can be clinically helpful for differentiating lumbar spine movement disorders. Comparison between COR characteristics would have facilitated by numeric expression