[Tilting angle of the scapula].
The shoulder joint has the most freedom of range of motion in the human body. This joint is composed of the gleno-humeral joint, the acromio-clavicular joint, the sterno-clavicular joint and the scapulo-thoracic articulation. The scapula has a very important role in the scapulo-humeral rhythm in the shoulder motions, but the scapular position could be identified from the two roentgenograms from different distances in the same direction. Three points of the scapula were chosen to decide the plane of the scapula as below: A: The intersection of the vertebral border and the scapular spine, B: The inferior angle, C: The tuberos, infraarticularis. The two roentgenograms were taken using the distances of one and two meters from the X-ray tube to the X-ray film. The X-ray was concentrated on the point A of the scapula. Points B and C on each roentgenogram were measured by X-Y coordinates. The lengths of AB, BC and CA and the scapular angles (the medially tilting angle, the downward tilting angle and the upward rotation angle) were calculated by  using specific equations. The lengths of AB, BC and CA and the medially tilting angle of 16 scapulae (dry bones) were measured by using a caliper, and those were calculated by roentgenograms. Each measurement was almost accurate the length of AB, BC and CA; r equal 0.965, the medially tilting angle; r equal 0.928). Then the scapular angles of a human body determined from the roentgenographic examination in the standing position. Also the shoulder was loaded with five kg at the forearm and the length were reconfirmed. The results were as below: The medially tiling angles were 42.7 degrees +/- 1.3 degrees (n equal 50) in the resting position (R.P.) and 47.5 degrees +/- 2.0 degrees (n equal 23) in the five kg loaded position (5 L.P.) among the males. Those angles were 45.5 degrees +/- 2.6 degrees (n equal 19, R.P.) and 49.5 degrees +/- 2.1 degrees (n equal 13, 5 L.P.) among the females. The downward tilting angles were 8.5 degrees +/- 1.6 degrees (R.P.) and 7.8 degrees +/- 2.0 degrees (5 L.P.) among the males and were 7.7 degrees +/- 2.6 degrees (R.P.) and 5.1 degrees +/- 4.8 degrees (5 L.P.) among the females. The upward rotation angle was 8.7 degrees +/- 0.9 degrees (R.P.) and was 5.6 degrees +/- 1.5 degrees (5 L.P.) among the males, and was 6.6 degrees +/- 1.8 degrees (R.P.) and was 4.4 degrees +/- 2.6 degrees (5 L.P.) among the females.
D000328:Adult; D005260:Female; D006801:Humans; D008297:Male; D011187:Posture; D011859:Radiography; D012146:Rest; D012540:Scapula / Q000000981:diagnostic imaging* / Q000502:physiology; D012737:Sex Factors