[Anterosuperior instability of the shoulder. Apropos of a case]

One case of antero superior instability, isolated, without traumatic history, revealed by blocking when raising arm in internal rotation, without hyperlaxity is reported. The radiographs in blocking position, on axillary view, revealed an asymetric antero superior subluxation of the humeral head, superimposed with the horizontal portion of the coracoid. During operative procedure by a deltopectoral approach, there was a gap between anterior border of the supraspinatus and the superior border of the subscapularis, increasing in internal rotation. A coracoidoplasty was made, in association with a stay suture between supraspinatus and subscapularis. The follow up was nineteen months, the result was good, with a stable and painfree shoulder and a normal motion.