anatomy denoting structures (muscles, arteries, nerves, glands, and others) that are auxiliary (normally present) or supernumerary (anomalous) to another more typical or larger structure of the same type. Most often, accessory structures are duplication variations.
[L. accessorius, fr. ac-cedo, pp. -cessus, to move toward]
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Examples: glitazone, GI cocktail, etc.