Floating AIGHL


Axial T1 MRAr.: Classic osseous Bankart lesion with nicely demonstrated cleft of intraarticular contrast insinuating into the osteocartilaginous fracture.	Sagittal T1 MRAr.: The disruption of the anterior inferior glenoid rim and labro-periosteal structures is shown as a linear vertical defect of contrast, and an amorphous torn labrum and periosteum anterior to it.


Coronal T2: In the same patient, there is a double axillary pouch sign, as well as a normal inferior labrum.	Axial T1 MRAr.: The humeral end of the anterior band of the inferior glenohumeral ligament is shown as disconnected from the medial humeral metaphysis.

Comments

This case corresponds to an 18 year-old male with a history of "shoulder popping out of the socket." The interest of the case lies in the fact that the history of recurrent unidirectional anterior instability correlates on imaging with not only a classic Bankart lesion with an osseous fragment, but also with a more subtle abnormality: an avulsed anterior band of the inferior glenohumeral ligament from the humeral metaphysis. Note that there is no edema on T2, indicating that the patient is being imaged not because of any acute episodes of trauma, but rather as a result of a history of recurrent dislocations and instability.

An avulsion of the anterior band of the inferior glenohumeral ligament or HAGHL (aka HAGL) is a relatively well-known condition in isolation. In a small proportion of cases, it can be diagnosed radiographically as a result of a small sliver of cortical bone avulsed off the humerus (osseous HAGHL).

In our case, both a Bankart lesion and a HAGHL coexist as a result of a more extensive disruption of the capsular structures during an episode of dislocation, or as a sequela of separate episodes. The result is a functionally floating anterior band of the inferior glenohumeral ligament or floating avulsed inferior glenohumeral ligament (floating AIGHL).