[Antero-internal impingement of the shoulder]

Anteromedial conflicts of the shoulder are situated in the subcoracoid or coracohumeral space, in the anterior part of the acromio-coracoid vault. The authors describe a first fibrous band connecting the anterolateral border of the acromio-coracoid ligament to the coraco-biceps tendon (Apoil) and a second deeper band between the superior border of the subscapularis and the insertion of the long head of biceps onto the labrum (Patte). The role of the vault varies according to constitution (length and direction of the coracoid process) and acquired factors (iatrogenic or traumatic); the role of the floor depends on numerous elements: traumatic sequelae (malunion), eccentricity of the humeral pivot, lesion of the rotator interval, variant of insertion of the anterior capsule, floating glenoid labra, anomalies of insertion of pectoralis minor. There are no pathognomonic signs, but Gerber's, Hawkin's and Yocum's signs are generally observed. Computed tomography and CT arthrography are currently the most reliable complementary investigations to demonstrate this type of conflict. This regional pathology is situated at the crossroads between pure conflictual mechanisms and hyperlaxity phenomena associated with subluxations.