An ultrasonic surgical instrument is provided which includes a handle assembly (218), a body (220) extending distally form the handle assembly and an end effector (222) configured to effect cutting, dissection, coagulation and/or ligation of tissue. The end effector (222) includes an ultrasonic member (226). A transducer (32, 132) is supported adjacent, on or within the ultrasonic member (226) and is connected to a power source. Upon actuation of the power source, the transducer (32, 132) effects vibration of the ultrasonic member (226). In one preferred embodiment, the end effector (222) is mounted for articulation about the distal end of the instrument. A sensor is positioned on the ultrasonic member for monitoring ultrasonic impedance, electrical impedance or temperature of tissue to be operated upon.
