抄録
This study investigated the relation ship between the slope and shape of the acromion and the spur at the antero-inferior surface of the acromion no clarify the cause of subacromial impingement. This investigation was performed with 205 scapular dry bone specimens. The specimens of 107 males were used. Their ages ranged from 20 to 83 years with an average age of 56.5 years. The presence of acromial spurs was identified. All acromions were classified visually as type I (flat), type II (curved) or type II (hooked) as described by Bigliani et al. And the slope of the acromion was measured in all specimens.
A spur at the antero-inferior surface was seen in 96 acromions (46.8%). And almost all spurs were located in the anterior one third of the acromion. In all specimens, fifty-six acromions (27.3%) were type I, one hundred and eight (52.7%) were type II and forty-one (20.0%) were type III. The type of acromion was not related to the presence or absence of a spur. The average slope of all acromions was 46±8°, that of acromions with spur was 44±7° and that of acromions without spur was 49±8°. There was a significant difference between the slope of the acromion with spur and acromions without spur. From this study it can be concluded that the type of acromion had no relation ship to subacromial impingement and the flattened slope of the acromion might be one cause of subacromial impingement.
