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Updated: May 6, 2026
Quantification of Levator Ani Hiatus Enlargement by Magnetic Resonance Imaging in Males and Females with Pelvic Organ Prolapse
Published on: April 17, 2019
Quantification of pelvic soft tissue artifact in multiple static positions
Reiko Hara1, Morgan Sangeux2, Richard Baker3
1Department of Physiotherapy, The University of Melbourne, Melbourne, Australia; Hugh Williamson Gait Analysis Laboratory, Royal Children's Hospital, Melbourne, Australia.
Pelvic skin marker displacement, a source of soft tissue artifact (STA) in gait analysis, is significantly influenced by hip flexion. Anterior superior iliac spine (ASIS) markers showed greater displacement, impacting pelvic kinematics during activities with substantial hip movement.
Area of Science:
- Biomechanics
- Clinical Gait Analysis
- Human Movement Science
Background:
- Soft tissue artifact (STA) is a primary error source in clinical gait analysis.
- Multiple calibration techniques aim to mitigate STA in kinematic data.
- Understanding pelvic marker displacement is crucial for accurate gait analysis.
Purpose of the Study:
- To investigate pelvic skin marker displacement relative to anatomical landmarks.
- To assess marker displacement across various body positions and hip flexion angles.
- To quantify the impact of pelvic STA on gait kinematics.
Main Methods:
- Assessed pelvic marker displacement in 20 healthy adults across nine body positions.
- Included positions with 90° and 45° hip flexion, maximum hip extension, and pelvic tilt.
- Correlated hip flexion angle with marker displacement magnitude and direction.
Main Results:
- Anterior superior iliac spine (ASIS) markers exhibited greater displacement than posterior superior iliac spine (PSIS) markers.
- Significant displacement (up to 17 mm) occurred during hip flexion.
- A strong correlation (r² = 0.70) was found between hip flexion angle and marker displacement.
- Mean ASIS surface displacement was 17 mm between standing and supine positions.
Conclusions:
- Pelvic marker displacement, particularly at the ASIS, increases with hip flexion.
- This displacement can affect inter-ASIS distance and hip joint center estimation.
- Activities involving large hip flexion may lead to greater STA and impact pelvic kinematics in gait analysis.
