Abstract
The rotator cuff works as an important stabilizer in the shoulder joint. However, it is difficult to estimate the rotator cuff function objectively. We have originated a roentgenographical technique, named “Scapula 45”, which has been easily applied in clinical cases.
Prior to deciding the condition of the X-ray exam., we confirmed t h e ratio of electrical activity of the rotator cuff muscles and settled the position of the shoulder joint. The measurement of the adaptation of the humeral head and the glenoid was named “Cuff index”. The assessments of the scapulo-humeral rhythms were measured and the angle was named “Scapula index”.103 cases with shoulder problems were examined and treated.
32 normal shoulders were examined as a control. The results of the cuff index in the normal group indicated that the scattering of each data was clearly seen at the arm by the side position. The dispersed data came up and assembled at the position of 45° elevation on the scapular plane, and this tendency became clear with a 3kg weight loading in the same position. There was no incidence of a below zero in the scapula index.
According to the electrom y ographical estimations, the activity of the supraspinatus muscle in the normal group gradually increased following an increased weight loading. Compared with the normal group, cases with a shoulder disorder tended to show a decrease in muscle activity.
From these results, we could confirm that the degree of the “cuff index” reflected the cuff muscles' functions clinically and electromygraphically.
We believe our original roentg e nographic technique will be an outstanding objective estimation of the relative functions of the rotator cuff.
