From:  Osteoporosis: definition, diagnosis, and considerations prior to starting treatment

 Definitions related to bone mass.

ParameterDefinitionUnit
Bone mineral density (BMD)Reflects the total amount of minerals within a specific volume or area of bone tissue, serving as a key indicator of bone strength and structural integrity. Commonly measured by DXA.g/cm2
Bone mineral content (BMC)Represents the total amount of mineral contained within a specific segment of bone, thus reflecting the absolute quantity of mineralized bone, serving as an indicator of bone strength and mass.g
Areal BMD (aBMD)A measure of the concentration of mineral content within a defined two-dimensional area of bone, widely used clinically to assess bone strength and fracture risk. Calculated by dividing the BMC by the two-dimensional projected bone area.g/cm2
Volumetric BMD (vBMD)Represents the three-dimensional mineral density of bone tissue, enabling differentiation between trabecular and cortical bone compartments.mg/cm3

DXA: dual-energy X-ray absorptiometry.