Abstract: Disclosed is an arrangement for use in transesophageal ultrasonic imaging of the heart (and other translumenal applications) in which both the position and orientation of an ultrasonic probe that generates an ultrasonic scanning pattern is determined in terms of a three-dimensional coordinate system that lies outside the patient's body and is produced by a magnetic field generator. The arrangement provides two-dimensional multi-planar scanning in which the ultrasonic scanning pattern is selectively positionable relative to rotation about two orthogonal coordinate axes that are mutually orthogonal to the longitudinal axis of the ultrasonic scanning probe. Provision is made for generating electrical signals indicative of rotational position of the scanning pattern relative to each of the two axes of rotation.