I WAS DRIVING THE MOTORCYCLE ON A 4 LANE DIVIDED HIGHWAY IN THE INSIDE LANE, WHEN (AT ABOUT 55 MPH) I SHIFTED INTO 5TH GEAR AND HEARD A "CLUNK" SOUND IN THE TRANSMISSION, AND THE REAR WHEEL SUDDENLY LOCKED UP AND THE BIKE WENT INTO A SKID (THERE WAS A LOT OF TRAFFIC BEHIND ME, AS WE HAD JUST LEFT A HEAVILY POPULATED SIGNAL ON THE ROADWAY AND MY RIDING PARTNER (MY WIFE) WAS IN FRONT OF ME). SINCE THERE WAS A LOT OF TRAFFIC BEHIND ME, I TRIED TO CONTROL THE SKID AS LONG AS POSSIBLE AND STEER INTO THE GRASSY MEDIAN TO AVOID BEING RUN OVER BY VEHICLES BEHIND ME. HOWEVER, ONCE THE FRONT TIRE MADE CONTACT WITH THE GRASSY MEDIAN, THE REAR TIRE (WHICH WAS STILL LOCKED UP) SLID AROUND, AND I WAS EJECTED FROM THE BIKE AT APPROXIMATELY 30 MPH. I SUSTAINED NON-LIFE THREATENING INJURIES TO MY RIGHT SHOULDER, BACK AND SIDE. THE REAR TIRE IS STILL LOCKED UP, AND THE BIKE CANNOT BE PUSHED OR MOVED WITHOUT SOME TYPE OF LIFT TO GET THE REAR WHEEL OFF THE GROUND. *TR