Tubercle of Assaki

Last revised by Henry Knipe on 4 Oct 2022

The tubercle of Assaki, also known as the tubercle of Asskay 3, is a small bony protuberance of the central part of the glenoid fossa with accompanying thinning of articular cartilage in this location 1.

It is presumably caused by the constant pressure of the humeral head exerted on the inferior glenoid fossa 3. It is believed to be closely related to the glenoid bare spot, which is found in the same location. Some authors treat both these entities as practically identical 2.3.

The tubercle of Assaki is a small (about 6 mm of average diameter 2) thickening of subchondral bone of the glenoid fossa, which is overlaid by the area of thinned cartilage known as glenoid bare spot 2.

Like the glenoid bare spot, it is best appreciated using fluid-sensitive sequences like T2 FSE in coronal and axial planes and it should not be mistaken for a cartilage defect 1.

The tubercle was first described by a French anatomist, Asskay 3.

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