Full shoulder motion relies on normal movement of the scapula (shoulder blade). The scapula has three main motions: internal rotation, upward rotation, and forward tipping. In this study, three dimensional (3-D) analysis of scapular movement was performed on two groups of adults.
Both groups had 17 members. Group 1 had loss of shoulder motion for unknown reasons. Group two had normal motion and no reported shoulder problems. Researchers used a magnetic motion capture system to compare scapular motion between the two groups.
Motion was tested in the standing position. Each person moved the arm through five repetitions of shoulder forward elevation. The results showed that people with impaired shoulder motion had greater scapular upward rotation compared to their other (normal) arm and compared to the normal group.
The authors suggest the increased scapular motion is one way the shoulder compensates or makes up for a loss of shoulder joint motion. Patients having trouble with daily activities because of decreased shoulder motion may benefit from a rehab program to restore normal scapular motion.