A method and apparatus is provided for annotating an image captured by an ultrasound system, which has an input device with a plurality of console keys for receiving input from an operator. The plurality of console keys includes an alphanumeric input device, such as a keyboard, used for placing characters on the image. An annotation function is invoked by pressing a key of the alphanumeric input device. The annotation function is for placing a character on the image in response to a character code from the alphanumeric input device. In a further aspect of the invention, the input device is provided with a pointing device, such as a track ball, which is spaced apart from the alphanumeric input device such that unintentional invocation of the annotation function is minimized. According to the method of the present invention, a key of the alphanumeric input device is pressed. In response to a character code generated by pressing the key, the annotation function is invoked. Subsequent pressing of a key on the alphanumeric input device generates subsequent character codes, which are placed on the image displayed by the ultrasound system.