Presentation
Trauma in hyperabduction in a classical ballet dancer.
Patient Data
MRI arthrography
Coronal T1 FS image demonstrates humeral avulsion of the posterior band of the Inferior glenohumeral humeral ligament (IGHL) from its humeral insertion with an intact labrum; there’s also “J sign” of the lax inferiorly displaced fibers (arrow) and extravasation of intra-articular contrast. There are also appearances of repair of intra-articular lesion of the supraspinatus tendon.
Coronal fat-saturated T1-weighted MR arthrogram shows “J” sign with disruption of humeral attachment of inferior glenohumeral ligament and subsequent contrast extravasation along medial humeral neck.
The anterior band of IGHL is normal.
Case Discussion
The inferior glenohumeral ligament (IGHL) complex is comprised of three components. It consists of an anterior band, a posterior band, and an interposed axillary pouch. The anterior band usually is thicker than the posterior band. HAGL lesion is an important cause of anterior instability at the glenohumeral joint. An MRI arthrogram or joint effusion distends the joint and allows for better visualization of IGHL defects. Specifically, the "U-shaped" axillary pouch stretched out of fluid becomes a "J-shaped" structure with extravasation of the contrast medium through the torn humeral attachment. HAGL lesions can be classified using the West Point classification of humeral avulsion of the glenohumeral ligament (HAGL) which includes six types: anterior HAGL, anterior bony HAGL, floating anterior IGHL, posterior HAGL, posterior bony HAGL, and floating posterior IGHL.
Case courtesy Dr.ssa Eleonora Renzi.
Radiographer: TSRM Fabio Imola
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