Determination of reference ranges for normal upper trapezius elasticity during different shoulder abduction using...

Area of Science:

• Musculoskeletal Ultrasound
• Biomechanics
• Medical Physics

Background:

• Assessing upper trapezius (UT) muscle elasticity is crucial for diagnosing musculoskeletal disorders.
• Establishing normal reference ranges for UT elasticity is essential for accurate clinical interpretation.
• Shear wave elastography (SWE) offers a non-invasive method to quantify muscle stiffness.

Purpose of the Study:

• To determine reference ranges for normal upper trapezius (UT) muscle elasticity.
• To investigate UT elasticity during different shoulder abduction angles (0° and 90°).
• To analyze the influence of factors like gender, UT thickness, age, and BMI on UT elasticity.

Main Methods:

• Eighty healthy participants underwent SWE measurements of UT elasticity.
• Measurements were taken at the left and right shoulder at 0° and 90° passive abduction (L0°, R0°, L90°, R90°).
• Statistical analysis was performed to assess the impact of various factors and calculate reference ranges using the normal distribution method.

Main Results:

• UT elasticity varied significantly with shoulder abduction angle (P < 0.0001).
• Males exhibited significantly higher UT elasticity than females at 90° abduction (L90°: P < 0.05; R90°: P < 0.01).
• Specific reference ranges were established for L0°, R0°, L90°, and R90°, with distinct ranges for males and females at 90° abduction.

Conclusions:

• Gender is a significant factor influencing upper trapezius elasticity at 90° shoulder abduction.
• The established reference ranges provide quantitative baseline data for UT muscle assessment.
• These findings support the consideration of gender in SWE-based evaluations of UT muscle strain.