title: In vivo measurement of intervertebral creep: a preliminary report.
abstract: The purpose of this study was to measure the in vivo intervertebral motion in normal human L4-L5 spinal motion segments. The quasi-static sagittal plane rotation, axial translation, and anterior-posterior shear translation were continuously measured in two subjects over a 5-min period, during which time the subjects sat quietly and maintained strict postures. A mechanoelectrical transducer rigidly fixed to the motion segment measured the relative motion. During the test period, the predominant motion occurred in the axial direction whereas coupled rotation and shear translation were not detected. The overall relative axial translations for each of the subjects were the following: -0.2 mm (subject 1),-1.1 mm (subject 2), and-0.9 mm (subject 2 repeat). Distinct modulating effects of respiration were observed superimposed on the intervertebral motion.
authors.affiliation: McClure Musculoskeletal Research Center, University of Vermont, Burlington, Vermont, USA.
authors.forename: A M
authors.initials: AM
authors.lastname: Kaigle
authors.forename: M
authors.initials: M
authors.lastname: Magnusson
authors.forename: M H
authors.initials: MH
authors.lastname: Pope
authors.forename: H
authors.initials: H
authors.lastname: Broman
authors.forename: T
authors.initials: T
authors.lastname: Hansson