ADIR position
The ADIR (ADduction and Internal Rotation) position relates to MR arthrography of the shoulder joint.
When added to a neutral-position shoulder protocol, MR arthrography in the ADIR position facilitates the diagnosis of labroligamentous lesions in patients with recurrent shoulder dislocations, particularly anterior labroligamentous periosteal sleeve avulsion (ALPSA) lesions and possibly other types of Bankart lesions, that is the classic Bankart and Perthes lesions.
The patient's pertinent hand is placed behind the back, thereby pulling the humeral head anteroinferiorly. This results in tensing of the posterior capsule with concurrent anterior capsule distension, which pulls contrast material into the anterior potential space.