Variability of femoral muscle attachments

Area of Science:

• Biomechanics
• Musculoskeletal modeling
• Human anatomy

Background:

• Musculoskeletal models often use single values for anatomical parameters, ignoring natural variation.
• This simplification may lead to inaccurate biomechanical analysis results.
• Understanding anatomical variability is crucial for reliable simulations.

Purpose of the Study:

• To investigate the influence of inter-individual anatomical variability on thigh muscle moment arms.
• To quantify the impact of anatomical variations on biomechanical modeling parameters.
• To highlight the need for considering anatomical ranges in simulations.

Main Methods:

• Digitized muscle origins and insertions on the femur in six specimens.
• Measured muscle volumes and computed attachment areas and centroid locations.
• Calculated the range of muscle moment arms to assess variability's effect.

Main Results:

• Significant variability observed in muscle attachment area (70% SD), muscle volume (80% SD), and centroid location (80% SD).
• Moment arms of the gluteus maximus and rectus femoris muscles showed high sensitivity to anatomical variations (65% SD).
• Inter-individual differences substantially affect key biomechanical parameters.

Conclusions:

• Anatomical variability critically influences musculoskeletal modeling outcomes, especially muscle moment arms.
• Simulations of musculoskeletal interactions must analyze sensitivity to anatomical variations.
• Using multiple anatomical configurations is recommended over a single mean dataset to prevent misinterpretation.