View Full Version : pelvis motion and Soft tissue artifact

01-04-2010, 08:47 AM
Dear Biomech-L subscriber,

We intend to use a marker cluster on LPSI and RPSI points of pelvis in gait analysis
exams. However, research presented in GCMAS/2007 (1) showed deformation of soft
tissues in the anterior (LASI and RASI) and posterior (LPSI and RPSI) positions of
the pelvis.

We did some tests and calculate the angle between LPSI-RPSI and LASI-RASI vectors
with the transverse plane of the laboratory in some subjects with normal gait - this
angle is similar to the Pelvic Obliquity angle. The two vectors have different
angles, especially in the initial contact: for the left gait cycle, the
LPSI-RPSI/ground angle is positive and the LASI-RASI/ground is negative (pelvis seems
twisted due to the marker displacement).

I would like to know if some gait laboratory develops researches on STA in the
pelvis, cluster marker use or new points of positioning for markers in pelvis.

Thank you for your attention.
Best Regards and happy new year.

Wagner de Godoy
HIAE - Brazil

Adam Rozumalski, Michael H. Schwartz1, Tom F. Novacheck1, Roy Wervey1, Andrew
Swanson, Daryll C. Dykes