SCATTERING OF ULTRASOUND FROM SKELETAL-MUSCLE TISSUE

The purpose of this paper was to explore the mechanisms which are resp onsible for the scattering of ultrasound from skeletal muscle tissue. It was undertaken in response to an interesting phenomenon observed in our laboratory whereby scattering power from avian skeletal muscle ch anges in concordance with passive stretch. Ultrasonic scattering from skeletal muscle samples was measured as they were stretched passively in increments of 10% of original length up to 40%. The samples were il luminated with an ultrasound beam from a transducer which was oriented orthogonally and at 20-degrees from the normal to the long axis of th e muscle sample. It was found that the integrated backscatter increase d significantly over the strain range for the orthogonal orientation b ut it changed very little after the initial stretch when the orientati on was 20-degrees. It is postulated that this phenomenon may be caused by reorientation of the endomysial collagen fibers surrounding each m uscle fiber.