A system (100) for registration of a bone structure includes a registration probe (108) and a processing circuit (106). The registration probe includes a two-dimensional array (110) of a plurality of ultrasonic transducers coupled to a rounded tip of the probe, wherein the ultrasonic transducers are configured to provide ultrasonic data. The processing circuit is configured to receive ultrasonic data from the ultrasonic transducers, determine which of the ultrasonic transducers are in contact with anatomy of a patient, generate registration points based on the ultrasonic data and the determination of which of the ultrasonic transducers are in contact with the anatomy of the patient, and register the anatomy of the patient to a model of bone using the registration points.
