Bone Aging, Osteoporosis, and Fracture Classifications

Comprehensive practice flashcards covering the effects of aging on bone, osteopenia, osteoporosis causes and treatments, DEXA scans, and bone fracture classifications.

How does aging affect the tensile strength of bone connective tissue?

Tensile strength decreases due to a reduced rate of protein synthesis of osteoid by osteoblasts, causing a relative increase in inorganic minerals (such as calcium phosphate) in the matrix, making bones brittle and susceptible to fracture.

What is demineralization, and what condition does it lead to as bone mineral density decreases?

Demineralization is the loss of calcium and other minerals from bone tissue, causing bones to become thinner and weaker. This decreases bone mineral density (BMD) below typical reference values, leading to osteopenia.

At what age does age-related bone mass reduction typically begin, and why?

It begins as early as 35-40 years of age because osteoblast activity declines while osteoclast activity continues at previous levels.

Which parts of the skeleton lose relatively large amounts of mass during aging, and what are the consequences?

The vertebrae, jaw bones, and epiphyses lose large amounts of mass, resulting in reduced height, loss of teeth, and fragile limbs.

What is a DEXA scan, and how is it used to assess bone health?

A dual-energy x-ray absorptiometry (DEXA) scan is a noninvasive procedure similar to an x-ray that provides images and calculations to determine if bone mass is normal for age, slightly reduced (osteopenia), or significantly reduced (osteoporosis).

What are the most common fracture sites associated with osteoporosis?

The wrist, hip, and vertebral column.

Why are menopausal individuals at increased risk for developing osteoporosis?

They have less bone mass than other individuals, begin losing bone mass as early as 35 years of age, and no longer produce significant amounts of estrogen, which normally helps protect against osteoporosis by stimulating bone growth.

Why do astronauts and patients undergoing cancer treatments face an increased risk of osteoporosis?

Astronauts experience reduced mechanical stress on bones due to the lack of gravity, causing bones to remodel and become less dense. Cancer treatments (including radiation, chemotherapy, and selected medications) exert adverse effects directly on bone density.

What type of physical activity has the greatest impact on preserving bone density?

Weightbearing activities, such as weight training, running, and walking.

Do calcium supplements with vitamin D alone stimulate new bone growth?

No, calcium supplements with vitamin D help maintain bone health, but by themselves they will not stimulate new bone growth.

How do bisphosphonates work to treat osteoporosis, and what examples are given?

Bisphosphonates (e.g., alendronate [Fosamax], risedronate [Actonel], ibandronate [Boniva]) work by interfering with osteoclast function, thereby retarding the removal of bone during remodeling.

What adverse effect is linked to bisphosphonates, and what is the recommended treatment timeframe?

Bisphosphonates are implicated in an increased risk of osteonecrosis (bone death) of the mandible (lower jaw) and other bone growth abnormalities, so patients are usually recommended to take them for no more than 5 years.

What is the key difference between a simple fracture and a compound (open) fracture?

In a simple fracture, the broken bone does not penetrate the skin, whereas in a compound fracture, one or both broken ends of the bone protrude through the skin.

What is the difference between a stress fracture and a pathologic fracture?

A stress fracture is a thin break caused by repetitive loads from increased physical activity (e.g., in runners), whereas a pathologic fracture occurs in a bone that has been weakened by disease.

What defines an avulsion fracture?

A fracture where a bone fragment is pulled off or separated from the rest of the bone by a soft tissue attachment.

What is a Colles fracture, and what distinct deformity does it cause?

A Colles fracture is a fracture of the distal end of the lateral forearm bone (radius) that produces a 'dinner fork' deformity.

What is the difference between a comminuted fracture and a complete fracture?

In a comminuted fracture, the bone is splintered into several small pieces between the main parts, whereas in a complete fracture, the bone is broken into two or more pieces.

How are compression fractures and depressed fractures characterized?

A compression fracture occurs when a bone is squashed (such as a vertebra during a fall), while a depressed fracture occurs when the broken part of the bone forms a concavity (such as in a skull fracture).