A microconvex-linear ultrasound probe is used to image the insertion of a needle into a subject with a microconvex portion of a transducer array of the probe, then image penetration of the needle toward target anatomy with a linear portion of the transducer array by rotation of the probe against the subject. Ultrasound images produced by the probe are consistently displayed by control of a scan converter with an orientation signal. The orientation signal results from the processing of accelerometer signals from the probe, the identification of a portion of the transducer array which is in acoustic contact with the subject, and/or the identification or tracking of a feature in the ultrasound images such as the target anatomy.