Abstract: A head restraint device for medical imaging apparatus, such as medical resonance imaging apparatus, is described. The device includes a base including a support for supporting the back of a subject's head. First and second arms are also provided, the proximal ends of the first and second arms being attachable to the base such that the distal ends of the arms are spaced apart from one another to form a region for receiving a subject's head. One or more head grips, which may include bone pins, are provided and attachable to the distal end of each of the first arm and second arm for engaging a head located in the region for receiving a subject's head. An arm positioning mechanism allows the spacing between the distal ends of the arms to be altered such that the size of the region for receiving the subject's head can be adjusted.