Modelling skin pelvic landmark coordinates into corresponding internal bone for wheelchair users

Area of Science:

• Biomedical Engineering
• Anatomy
• Biomechanics

Background:

• Accurate identification of pelvic landmarks is crucial for clinical applications.
• External landmarks are often used as surrogates for internal pelvic structures.
• Soft tissue overlying the pelvis can introduce inaccuracies in landmark identification.

Purpose of the Study:

• To investigate the relationship between internal and external pelvic landmarks using linear regression.
• To determine if body mass index (BMI) or skinfold thickness significantly influence these relationships.
• To compare the accuracy of manual digitization versus skin markers for identifying external pelvic landmarks.

Main Methods:

• Internal pelvic landmarks were identified using a stereoradiographic method.
• External pelvic landmarks were digitized manually or via skin markers.
• Linear regression models were employed to analyze the relationships between internal and external landmarks, incorporating BMI and skinfold thickness.

Main Results:

• External pelvic landmark coordinates generally differed statistically from internal ones.
• Manual digitization reduced soft tissue artifacts compared to skin markers.
• BMI and skinfold thickness were significant variables in regression models, particularly concerning soft tissue thickness directions.

Conclusions:

• Manual digitization of external pelvic landmarks is more accurate than using skin markers.
• Soft tissue thickness, influenced by BMI and skinfold measurements, affects pelvic landmark accuracy.
• Further research is needed to develop comprehensive models for understanding internal-external pelvic landmark relationships.