Abstract
Muscle injuries can be classified as extrinsic or intrinsic injuries as well as contusions and lacerations, and clinical assessment is composed of the history and physical examination. Diagnostic imaging, particularly ultrasound (US) examination, is essential to a correct assessment of the severity of the injury and to exclude important complications as these two elements influence treatment decisions, prognosis and time to return to unrestricted physical activity. This paper presents the main clinical and US features of acute muscle injuries.