Abstract: A device for repeatable positioning of a reference element on a human head comprises a standardized base in substantially the shape of a ring (1 ) with a support (2) for abutment against the back of the patient's head, an attachment means (10, 11) located on the ring (1) substantially diametrically opposite to the position of the support (2), an initially deformable first splint (20) detachably fitted in the attachment means (10, 11) and arranged to form a special bite piece for the patient, to be correctly bitten by the patient when the support (2) abuts the back of the head and the nose splint is correctly in contact with the region of root of the patient's nose.