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Bone Density ARRT Examination Review
Questions With Correct Answers
Osteroporosis - answer✔A skeletal disorder characterized by compromised bone strength
predisposing a person to an increased risk of fracture. Defined by World Health Organization
(WHO) based on bone mineral density (BMD) assessment BMD lies 2.5 standard deviations or
more below average value for young healthy women, T-score <-2.5 SD
Occurs when rate of bone resorption exceeds rate of bone formation=decrease in bone mass.
World Health Organization (WHO) - answer✔- In 1994, the WHO selected a BMD cut-point for
defining the prevalence of osteoporosis in the Caucasian post-menopausal female population.
- T score <-2.5 SD is considered Osteoporosis
Four categories of WHO: - answer✔
"WHO 8" - answer✔Clinical risk factors for fx age, low bone mass index, prior fx, parental hip fx,
current smoker, glucocorticoid use (3 mo), rheumatoid arthritis, excessive alcohol consumption
Primary Osteoporosis - answer✔Metabolic bone disease characterized by low bone mass &
deterioration of bone tissue=bone fragility and increased fx risk no direct or singular cause
Type 1= post menopausal osteoporosis (estrogen loss)
Type 2=age related osteoporosis
Two Types of Primary Osteoporosis: - answer✔Two types: Idiopathic
- Type I: Bone loss occurs in trabecular part of
bone; menopause
- Type II: Cortical bone; aging process
Primary Osteoporosis Risk Factors: - answer✔1. Age: increases with age
2. Genetics: runs in the family
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3. Sex: females have accelerated bone loss after menopause
4. Hormones: estrogen deficiency results in accelerated bone loss
5. Nutritional: inadequate vitamin D, calcium
6. Physical activity: inactivity promotes osteoporosis
7. Environmental factors: smoking, alcohol promote osteoporosis
Secondary Osteoporosis - answer✔Secondary to or caused by something else = direct cause
result from variety of chronic conditions that significantly contribute to bone mineral loss, or
result from effects of medications & nutritional deficiencies. Such as hyperparathyroidism, long-
term drug therapy, long-term immobility.
Support - answer✔Function for framework for attachment of muscles & tissues
Protection - answer✔Function to protect internal organs from injury
Movement - answer✔Function for bones act as levers & attachment for muscles
Mineral Storage - answer✔Function as reservoir for Ca and phosphorus, essential for cellular
activities
blood cell production - answer✔Function where hematopoiesis occurs in red marrow found
w/in bone cavities
Energy Storage - answer✔Function where lipids (fats) stored in adipose cells of yellow marrow
serve as an energy reservoir
Trabecular bone - answer✔- *20%* of skeletal body mass
- Spongy/honeycomb, *CANCELLOUS*
- Supports compressive loads
- *AXIAL* skeleton
- Most responsive to therapy
- Higher metabolic rate
- End of long bones
Cortical bone - answer✔- *80%* of skeletal body mass
- *COMPACT*, strong, dense
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- Resists twisting and bending motion
- *APPENDICULAR* skeleton
- Shaft of long bones
Three functions of the skeleton: - answer✔- Protect vital organs
- Scaffolding for the musculoskeletal system
- Manufactures red blood cells
Axial skeleton includes: - answer✔Primarily trabecular bone. Skull, vertebral column, sternum
and ribs.
Appendicular skeleton includes: - answer✔Primarily cortical bone. Scapula, extremities and
pelvic girdle.
Bone - answer✔Structural anatomy is for weight bearing & non-weight bearing.
Weight-bearing includes: - answer✔Lower extremities, spine, calcaneus, and portions of the
pelvic girdle.
Non-weight bearing includes: - answer✔The remainder of the skeleton
Cortical sites include: - answer✔Total body, femoral neck, fingers, proximal forearm and distal
forearm.
Trabecular sites include: - answer✔Spine, Ward's area (3 bundles of trabecular bone in femoral
neck area), calcaneus, and ultra distal forearm.
Central sites include: - answer✔- Thoracic and lumbar spine (spine-trabecular, weight bearing
and axial)
- Proximal femur
Peripheral sites include: - answer✔- Forearm- DXA,SXA, pQCT
- Heel - SXA, QUS
- Fingers - DXA, regular x-ray
- Tibia - QUS
Functions of bones: - answer✔Support
Protection