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Coracoid tip position on frontal radiographs of the shoulder: a predictor of common shoulder pathologies?
C U Schulz, MD1, H Anetzberger, MD2 and C Glaser, MD3
Department of Orthopaedic Surgery, Ludwig Maximilians Universitaet Munich, Germany, 2 Department
of Orthopaedic Surgery, Technische Universitaet Munich, Germany and 3 Department of Radiology,
Ludwig Maximilians Universitaet Munich, Germany
The coracoacromial arch is a static anterior–superior stabilizer of the humeral head. Thus coracoacromial
arch inclination, which varies depending on coracoid tip position, may be related to shoulder pathologies.
Therefore, we retrospectively analysed coracoid tip positions in the true anterior posterior view of different
shoulder pathologies: reference shoulders (n=27), shoulders with rotator cuff tear (supraspinatus tear n=29;
subscapularis tear n=21) and shoulders with anterior glenohumeral instability (traumatic n=17; atraumatic n=14).
In supraspinatus tear shoulders, the coracoid tip projected onto inferior glenoid half in 86% of cases
(type I coracoid), extending more inferiorly compared with reference group (p=0.0002) or subscapularis
tear shoulders (p<0.0001). In contrast, 78% of cases with subscapularis tear show the coracoid tip projected
onto the superior glenoid half (type II coracoid). Atraumatic glenohumeral instabilities had a more superior
coracoid tip position than traumatic instabilities (p=0.04), but no differences were observed on basis of
coracoid type or in comparison with normal controls. We conclude that coracoid tip position is highly variable.
Since type I coracoids are predominant in shoulders with supraspinatus tears and type II coracoids in shoulders
with subscapularis tears, coracoid tip position may thus provide a simple diagnostic complement for a probable
site of rotator cuff tears.
British Journal of Radiology (2005) 78, 1034-1037
© 2005 British Institute of Radiology
doi: 10.1259/bjr/22941655
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