A kinematic model of the shoulder complex to evaluate the arm-reachable workspace.
Upper-arm evaluation including shoulder motion in physiotherapy has no three-dimensional tool for an arm-functioning evaluation, which hampers an uniform, objective comparison. Human shoulder complex models suffer from lack of shoulder girdle kinematic data. A kinematic shoulder-complex model with six degrees of freedom is proposed as the composition of the inner joint representing the shoulder-girdle joints and outer joint representing the glenohumeral joint. The outer shoulder joint has three perpendicular rotations: adduction/abduction, retroflexion/flexion and internal/external rotation of the humerus. The inner shoulder joint has two rotations, depression/elevation and retraction/protraction, and one translation, which are all dependent on the elevation angle of the humerus. The human arm-reachable workspace that represents the area within reach of the wrist is calculated on the basis of the shoulder-complex model and the additional elbow-joint direct kinematics. It was demonstrated that cross-sections of the calculated workspace are in agreement with the measured arm-reachable workspace in all three anatomical planes. The arm-reachable workspace volume and graphics were calculated and a comparison of the arm's workspaces during a patient's shoulder treatment was made. The obtained numerical and graphical arm-reachable workspaces can be used for arm-functioning evaluations in rehabilitation and ergonomics.
Klopcar
N
N
Jozef Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia. nives.klopcar@ijs.si
Tomsic
M
M
Lenarcic
J
J
D001132:Arm / Q000033:anatomy & histology / Q000502:physiology; D001696:Biomechanical Phenomena; D003198:Computer Simulation; D006801:Humans; D007592:Joint Diseases / Q000473:pathology / Q000503:physiopathology / Q000628:therapy; D008953:Models, Anatomic; D008954:Models, Biological; D026741:Physical Therapy Modalities; D016059:Range of Motion, Articular; D012785:Shoulder Joint / Q000033:anatomy & histology / Q000502:physiology*