In a method for the non-invasive determination of the position and orientation of prominent structures inside the body of a human being or an animal, wherein the body is irradiated with ultrasonic radiation in the area of the prominent structure by means of an ultrasonic head which emits ultrasound and receives ultrasound, the ultrasonic radiation reflected on the prominent structure is received, and an image corresponding to the travel time of the reflected radiation is represented on a display, in order to determine the position of the prominent structure in the body, it is proposed that the position and orientation of the ultrasonic head and of the body in the area of the prominent structure be determined by means of a navigation system with the assistance of marking elements fixed to the ultrasonic head and to the body, that a prominent structure be selected on the display, that the position and orientation of the prominent structure relative to the ultrasonic head be determined on the basis of the radiating direction of the ultrasonic head and the measured travel time of the ultrasonic radiation, and that the position and orientation of the prominent structure relative to the body be determined from the position and orientation of the ultrasonic head relative to the body.