I have a broken leg and dislocated ankle. i've had it manipulated into plaster cast. how high should it be elevated overnight? as it is pulsating.

Throbbing pain: Sorry to hear that. Your injury will tend to swell which will eventually cause your cast to become tight, which in turn will increase the throbbing pain. Elevation above heart level ( if you are lying down) or above waist level if you are sitting, will help. Your doctor may have given you written instructions.

Above heart level: Will facilitate reduction of swelling.