Osteoblasts: a type of bone cell that builds-up bone. When bones build up, they undergo both synthesis (formation) and mineralization (elements are combined).
Osteoclasts: a very large bone cell which breaks down bone tissue, also referred to as remodeling. Normal healthy bones are constantly undergoing
Bone resorption: the process where the osteoclasts break down the bone and release the minerals into the blood stream, which results in calcium moving from within the bone to the blood.
Bone Remodeling: the breaking down of mineralized bone by osteoclasts followed by the synthesis of bone matrix by osteoblasts. The bone tissue will subsequently become mineralized.
Bone Matrix: consists of about 33% organic matter (mostly collagen) and 67% inorganic matter (calcium phosphate). The integrity of the bone matrix is critical for bone strength.
Bone Density or Bone Mineral Density (BMD): is the amount of minerals, ie: calcium and phosphorous contained in a certain volume of bone.
Low Bone Mass: is diagnosed when your bone mineral density (BMD) value at either the neck of your femur (hip joint) or in your lumbar spine (low back) or both that is between -1 and -2.5 standard deviations (SDs) below the mean (average) bone density (BMD) of the value of a young, healthy female adult.
DEXA scan (Dual-Energy X-ray Absorptiometry), also called a Bone Scan or a Bone Densitometry is an imaging modality where a very small dose of ionizing radiation (like having an x-ray) will be used to produce a image of your bones, specifically your wrist, femur and spine.
Osteopenia: osteo means "bone" and penia means "decrease or deficiency". Osteopenia is diagnosed when your BMD is low. Your DEXA scan "T-scores" will fall between -1 and -2.5 standard deviations below a young female adult.
Osteoporosis: osteo means "bone" and porosis means “porous bone.” Osteoporosis is diagnosed when your BMD is very low. Your DEXA scan "T-scores" will be less then -2.5 standard deviations below a young female adult.
However, you may also be diagnosed with osteoporosis if you have had a fragile fracture (see below) or you have a moderate or high 10-year fracture via a FRAX score (see below).