Development of Infrared Scapular Marker Clusters

Faculty Mentor

Joseph Kardouni

Location

Savannah Ballroom

Type of Research

On-going

Session Format

Poster Presentation

College

Waters College of Health Professions

Department

Biodynamics and Human Performance Center

Abstract

The scapula plays a key role in providing a dynamic and stable base for the glenohumeral joint to function optimally. Therefore, kinematically assessing scapular motion is critical for evaluating functional movement of the shoulder. Measuring scapular motion is challenging due to the bone being covered by multiple muscles and thus prone to motion artifacts from skin secured sensors. The acromion process (AC) is superficial and validated location for sensor fixation for when using a six-degree-of-freedom electromagnetic (EM) system. A limitation of EM tracking systems is high susceptibility to distortion from metal, particularly iron, in close proximity to their use. Optical motion capture systems are not affected by magnetic distortion but require a rigid, non-planar, asymmetrical arrangement of at least three reflective markers. Due to the limited size of the AC, such a cluster must be compact while still ensuring continuous and unambiguous tracking. The scapular spine presents another superficial landmark, although its larger anatomical span requires a lightweight design to minimize inertial artifact. Thus, the purpose of this study is to develop and validate optical marker clusters for placement on the AC and scapular spine as potential alternatives to an EM sensor. Anatomical measurements of the scapula were obtained using calipers, and prototypes were designed in SolidWorks, 3D printed, and refined to reduce mass and accommodate EM sensor placement. With Institutional Review Board approval, a method comparison study will be conducted using simultaneous EM and optical capture during shoulder flexion tasks. Data will be reduced relative to the thorax according to International Society of Biomechanics standards, and systematic bias and absolute deviation will be evaluated. This work aims to develop a metal-insensitive method for accurate scapular motion tracking.

Program Description

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Start Date

4-21-2026 10:00 AM

End Date

4-21-2026 12:00 PM

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Apr 21st, 10:00 AM Apr 21st, 12:00 PM

Development of Infrared Scapular Marker Clusters

Savannah Ballroom

The scapula plays a key role in providing a dynamic and stable base for the glenohumeral joint to function optimally. Therefore, kinematically assessing scapular motion is critical for evaluating functional movement of the shoulder. Measuring scapular motion is challenging due to the bone being covered by multiple muscles and thus prone to motion artifacts from skin secured sensors. The acromion process (AC) is superficial and validated location for sensor fixation for when using a six-degree-of-freedom electromagnetic (EM) system. A limitation of EM tracking systems is high susceptibility to distortion from metal, particularly iron, in close proximity to their use. Optical motion capture systems are not affected by magnetic distortion but require a rigid, non-planar, asymmetrical arrangement of at least three reflective markers. Due to the limited size of the AC, such a cluster must be compact while still ensuring continuous and unambiguous tracking. The scapular spine presents another superficial landmark, although its larger anatomical span requires a lightweight design to minimize inertial artifact. Thus, the purpose of this study is to develop and validate optical marker clusters for placement on the AC and scapular spine as potential alternatives to an EM sensor. Anatomical measurements of the scapula were obtained using calipers, and prototypes were designed in SolidWorks, 3D printed, and refined to reduce mass and accommodate EM sensor placement. With Institutional Review Board approval, a method comparison study will be conducted using simultaneous EM and optical capture during shoulder flexion tasks. Data will be reduced relative to the thorax according to International Society of Biomechanics standards, and systematic bias and absolute deviation will be evaluated. This work aims to develop a metal-insensitive method for accurate scapular motion tracking.