The Skin Acts to Maintain Muscle Shear Modulus

It is not clear how the tissues covering the skeletal muscles affect the muscles' mechanical properties. The main purpose of this study was to examine changes in muscle shear modulus as a representative mechanical property of muscle with and without the covering tissues of skin and epimysium (fascia). Shear modulus of the medial gastrocnemius (MG) muscle was determined using ultrasound shear-wave elastography in the Thiel's embalmed cadavers under three different conditions: original (intact cadavers), removal of the skin on the MG and subsequent removal of the epimysium. Muscle shear modulus significantly decreased by 50% after removal of the skin, whereas no additional changes in shear modulus were observed after subsequent removal of the epimysium. This study suggests that the skin is a main contributor for maintaining the muscle mechanical properties among tissues covering the skeletal muscle.