Friday, March 14, 2008

Bagels and HAGLs

The origin of the venerable bagel is still an issue for debate.

Most food historians have come to the conclusion that the bagel is of Jewish origin, probably created in Poland, sometime in the 17th century. In medicine, we are familiar with the BHAGL, which stands for Bony Humeral Avulsion of the Glenohumeral Ligament.

(BTW, the word "humerus" is actually a misspelled borrowing of the Latin work "umerus", which means "shoulder". I wonder if anyone was sued for linguistic malpractice over this.)

The HAGL lesion is a Humeral Avulsion of the Glenohumeral Ligament, i.e. a BHAGL without the bone avulsion. A HAGL injury occurs in the setting of anterior shoulder dislocation. In 1942, the orthopedic surgeon Toufick Nicola first described capsular avulsion of the IGHL (inferior glenohumeral ligament) from the humerus in patients following shoulder dislocation, so this injury is a well-known entity.

Despite this, this lesion may be overlooked at arthroscopy, so the radiologist can help alert the surgeon to look specifically for this lesion. Twenty year-old weightlifter with a shoulder dislocation 4 weeks ago, images from an MR arthrogram:

(click on image to enlarge)
There is a HAGL lesion (red arrows), with extensive edema. Contrast does not extravasate freely into the axilla because this is a subacute injury, and some healing has occurred. For comparison, here is a normal shoulder, with arrow denoting normal IGHL:

(click on image to enlarge)
A sagittal image from the injured patient shows the torn, lax anterior band of the IGHL:

Bui-Mansfield et al. have recently described a classification scheme for humeral avulsion of the glenohumeral ligament (AJSM 2007, 35:1960-1966). They divide these injuries into:

1) Anterior HAGL (tear anterior band IGHL at humerus)
2) Anterior BHAGL (anterior HAGL with a bone avulsion from the humerus)
3) Floating AIGHL (tear anterior band IGHL at the humerus and at the glenoid)
4) Posterior HAGL (tear posterior band IGHL at humerus)
5) Posterior BHAGL (posterior HAGL with a bone avulsion from the humerus)
6) Floating BHAGL (tear posteiror band IGHL at the humerus and at the glenoid)

Just writing this is making me glance at the toaster and reach for the cream cheese....

Vic David MD

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