TY - JOUR
T1 - Correspondence between scapular anatomical coordinate systems and the 3D axis of motion
T2 - A new perspective on an old challenge
AU - Lawrence, Rebekah L.
AU - Roseni, Kevin
AU - Bey, Michael J.
N1 - Funding Information:
The authors would like to thank the participants who volunteered for this study. R.L. would like to thank Paula Ludewig, PT, PhD, FAPTA for her mentorship and the many discussions that inspired the premise for this study. This work was supported by the National Institutes of Health (grant number K99AR075876). The NIH did not play a role in the design, conduct, or reporting of this study.
Funding Information:
The authors would like to thank the participants who volunteered for this study. R.L. would like to thank Paula Ludewig, PT, PhD, FAPTA for her mentorship and the many discussions that inspired the premise for this study. This work was supported by the National Institutes of Health (grant number K99AR075876). The NIH did not play a role in the design, conduct, or reporting of this study.
Publisher Copyright:
© 2022 Elsevier Ltd
PY - 2022/12
Y1 - 2022/12
N2 - Several scapular anatomical coordinate systems have been reported in the literature to describe shoulder kinematics. Unfortunately, the use of different conventions hinders comparison across studies. Further, inconsistencies between a coordinate system and the scapula's 3D axis of motion means that scapular motion will be incorrectly attributed to axes about which it did not rotate. The objectives of this study were to: 1) determine the extent to which the axes of four common scapular coordinate system conventions correspond to the 3D axis of scapular motion (i.e., instantaneous helical axis, IHA), and 2) report the prevalence of scapulothoracic gimbal lock for each convention. Shoulder kinematics were tracked during scapular plane abduction in 45 participants using biplane videoradiography. Scapulothoracic kinematics were described using the original convention proposed by van der Helm, the convention recommended by the International Society of Biomechanics (ISB), a glenoid-based coordinate system, and a glenoid-oriented coordinate system. The 3D angle was calculated between the IHA and each axis of the four conventions (IHA-axis angular deviations). A repeated measures ANOVA was used to compare IHA-axis angular deviations between conventions. The glenoid-oriented and ISB conventions resulted in the smallest and largest IHA-axis angular deviations, respectively (21.7°±3.6° vs. 30.5°±5.2°, p < 0.01). Gimbal lock was approached in 17.8% of participants when using the original convention, 2.2% when using the ISB convention, and 0% when using the glenoid-based or -oriented conventions. These findings suggest the glenoid-oriented coordinate system may be worthy of further consideration when investigating shoulder kinematics during scapular plane abduction.
AB - Several scapular anatomical coordinate systems have been reported in the literature to describe shoulder kinematics. Unfortunately, the use of different conventions hinders comparison across studies. Further, inconsistencies between a coordinate system and the scapula's 3D axis of motion means that scapular motion will be incorrectly attributed to axes about which it did not rotate. The objectives of this study were to: 1) determine the extent to which the axes of four common scapular coordinate system conventions correspond to the 3D axis of scapular motion (i.e., instantaneous helical axis, IHA), and 2) report the prevalence of scapulothoracic gimbal lock for each convention. Shoulder kinematics were tracked during scapular plane abduction in 45 participants using biplane videoradiography. Scapulothoracic kinematics were described using the original convention proposed by van der Helm, the convention recommended by the International Society of Biomechanics (ISB), a glenoid-based coordinate system, and a glenoid-oriented coordinate system. The 3D angle was calculated between the IHA and each axis of the four conventions (IHA-axis angular deviations). A repeated measures ANOVA was used to compare IHA-axis angular deviations between conventions. The glenoid-oriented and ISB conventions resulted in the smallest and largest IHA-axis angular deviations, respectively (21.7°±3.6° vs. 30.5°±5.2°, p < 0.01). Gimbal lock was approached in 17.8% of participants when using the original convention, 2.2% when using the ISB convention, and 0% when using the glenoid-based or -oriented conventions. These findings suggest the glenoid-oriented coordinate system may be worthy of further consideration when investigating shoulder kinematics during scapular plane abduction.
KW - Anatomical coordinate systems
KW - Gimbal lock
KW - Kinematics
KW - Scapula
UR - http://www.scopus.com/inward/record.url?scp=85142131216&partnerID=8YFLogxK
U2 - 10.1016/j.jbiomech.2022.111385
DO - 10.1016/j.jbiomech.2022.111385
M3 - Article
C2 - 36403529
AN - SCOPUS:85142131216
SN - 0021-9290
VL - 145
JO - Journal of Biomechanics
JF - Journal of Biomechanics
M1 - 111385
ER -