The invention applies to the field of image processing used to assist with medical diagnosis. More specifically, the invention relates to a method for processing images based on an image representing the larynx of a human being with a view to determining a degree of mobility of the vocal chords of said person. The method according to the invention comprises: a step (13) of determining, in the image, positions of the thyroid cartilage and the right arytenoid cartilage and/or the left arytenoid cartilage, and a step (14) of determining a characterisation parameter on the basis of the respective positions of said cartilages.