Method used to measure the length of glenohumeral joint in ultrasonography. A line was drawn from the lateral edge of the labrum (point 1) along the inferior margin of labrum (line A, red line). From the lateral edge of the labrum, a line (line B, yellow line) was drawn perpendicular to the line A. The distance from the lateral edge of the labrum (point 1) to the corresponding cortical echo of the humerus (point 2) on the line B was defined as the length of glenohumeral joint. HH, humeral head; Gl, bony glenoid.