抄録
[Purpose] The purpose of this study is to analyze the influence of the scapulothoracic joint on the rotator cuff function using integrated electromyography.
[Materials and Methods] Ten shoulders of ten young males who were diagnosed as having dysfunction of scapulothoracic joint with ⌈Scapula-45⌋ radiography and resisted abduction and external rotation test. The activities of the supraspinatus, infraspinatus, deltoid, and biceps were evaluated electromyographically with the loads at 45 degrees elevated position in the scapular plane. Subsequently the activity of these muscles was collected with a manual assist to the scapulothoracic function. The EMG activity was expressed as a percentage of the Max MMT (%MMT).
[Results] The EMG activity increased with the load in all the cases. In 80% of the total cases, the relationship between the supraspinatus and deltoid did not change irrespective of the load (deltoid/supuraspinatus=1 /1.3) without manual assistance. The %MMT of the supraspinatus and deltoid of these cases showed a significant difference between the activity with and that without manual assistance. The tendency was remarkable at 3kg load. In 20% of the total cases, a dysfunction of rotator cuff was noted.
[Conclusion] The results suggest the function of scapulothoracic joint has an effect on the rotator cuff function.
