A stylus assembly is adapted to be attached to a surgical jig. The stylus assembly comprises a body having first and second arms with a space therebetween for receiving a portion of the surgical jig, a stylus adjustably mounted relative to the body, and a locking member in use, actuation of the locking member from an unlocked to a locked position enables locking of the body to the surgical jig and locking of the stylus relative to the body.