Measurement of skin mobility in the upper back

Area of Science:

• Biomedical Engineering
• Dermatology
• Physical Medicine

Background:

• Manual palpation for skinfold tenderness is common in clinical practice.
• Previous assessments suggest increased resistance in patients with skinfold tenderness.
• The underlying mechanisms of this perceived resistance are not fully understood.

Purpose of the Study:

• To objectively evaluate skin mobility and tenderness using a novel suction device.
• To compare objective skin mobility measurements with subjective manual testing findings.
• To investigate the role of underlying muscle contraction in manual skinfold assessment.

Main Methods:

• Objective skin mobility was measured using a vacuum pump to create a stress/strain curve.
• Suction testing was performed on subjects with and without clinical skinfold tenderness.
• Skin mobility was compared between relaxed and contracted states of underlying muscles.

Main Results:

• No significant difference in skin mobility was found between subjects with and without skinfold tenderness via suction testing.
• Suction testing did not induce pain in subjects experiencing clinical skinfold tenderness.
• Underlying muscle contraction was found to reduce skin mobility by 50%.

Conclusions:

• The resistance felt during manual skinfold testing is likely due to pain-induced muscle contraction, not intrinsic tissue properties.
• Objective suction testing provides a more reliable measure of skin mobility, unaffected by muscle guarding.
• Clinical assessment of skinfold tenderness may require re-evaluation to differentiate between true tissue changes and artifactual resistance from muscle contraction.