TABLE 1.

Murine Shoulder Arthritis Score (MSAS) Scoring System

Points	0	1	2	3
Sphericity of Articular Portion of Humeral Head	100% spherical	80% spherical	50% spherical	mostly flattened/pitted
Cellularity	obvious hypocellular layer superficial to tidemark	reactive cellular layer superficial to tidemark	scant layer superficial to tidemark	tidemark difficult to distinguish/inconsistent
Subchondral Bone Morphology	well trabeculated subchondral bone without bone marrow close to osteochondral junction	scant bone marrow approaching osteochondral junction	<50% of subchondral bone infiltrated by marrow space	>50% of subchondral bone infiltrated by marrow space
Alcian Blue Staining	intense blue staining deep to tidemark	two separate areas of intense blue staining: one deep to tidemark and one superficial	one thin area of deep blue staining with tidemark unclear	disorganized
Pannus Present	no	-	-	yes