Article

Motion of human trunk segments in healthy subjects during activities
of daily living has been described either with oversimplified models or with
cumbersome techniques of isolated anatomical complex. This study describes
multi-segmental trunk motion based on a new technique which is a compromise
between technical limitations, implied with the experiments, and clinical
relevance. METHODS: The thorax segment was tracked by the optimal spatial
matching of four thoracic markers. The separate bi-dimensional shoulder line
rotations and translations with respect to the thorax were calculated by markers
on the two acromions. Spine motion was characterised by a 5-link-segment model
from additional four skin markers, in the anatomical reference frame based on
four pelvic spine markers. These 14 markers were tracked in 10 healthy subjects
and one clinical case during static upright posture, chair rising-sitting, step
up-and-down and level walking, and also during elementary flexion and extension,
lateral bending, and axial rotation movements of the entire trunk. FINDINGS:
Intra-subject repeatability over ten repetitions was found to be high for most of
the measurements, with average standard deviations of less than 1.8 degrees for
all planar rotations at the spine, and less smaller than 1mm for shoulder
translations. Large motion, albeit with different patterns, was found in all
subjects, also revealing interesting couplings over the three anatomical planes.
INTERPRETATION: Considerable subject-specific motion occurs at each of these
different trunk segments in all three anatomical planes, in simple exercises and
in motor tasks of daily living. Measurements taken with the present new trunk
model in pathological subjects shall reveal corresponding patterns and ranges of
motion in abnormal conditions.
CI - Copyright (c) 2011 Elsevier Ltd. All rights reserved.

Langue : ANGLAIS