ABSTRACT: In the human body, the skeletal structure provides mechanical support for movement. The shoulder joint has the greatest number of degrees of freedom in our body, allowing the arm to move in virtually all directions and angles. Physiotherapy treatment applied in the rehabilitation of movements is usually based on repetitive physical activities, and the evaluation of progress and recovery is a process conducted by physiotherapy professionals. For the evaluation of treatment progress, these professionals mostly use subjective visual criteria, and the use of automated equipment that generates numerical values or trajectory fields is only applied in some cases and usually in specialized centers. The article proposes the development of a device for measuring the range of motion of arm shortening in the movement of the glenohumeral joint, and the study of the results of associating the device with an existing passive exoskeleton positioned over the shoulder, which should perform the shortening movement reading specific electronic elements.