A METHOD FOR THE MEASUREMENT OF 3-DIMENSIONAL SCAPULAR MOVEMENT

Many disorders of the shoulder complex are accompanied by changes in t he pattern of scapular motion which is difficult to measure except rad iographically. In order to study the three-dimensional motion of the s capula which accompanies arm movements, a technique has been developed using a three-pointed locater which can be applied over three bony la ndmarks - the acromial angle, the inferior angle, and the root of the scapular spine. The spatial orientation of the locater relative to the trunk was measured using an electromagnetic movement sensor (ISOTRAK) which has been shown to be clinically reliable. Measurements of scapu lar plane rotations during abduction showed particularly good agreemen t with published data; variations in measurements of the out-of-plane angles were attributed to difficulties of contacting the acromion reli ably when the deltoid muscle was contracted. It is concluded that the system is suitable for clinical use in the study of shoulder pathology .