MEDICAL BIOLOGY, HUMAN ANATOMY, PHYSIOLOGY AND PATHOLOGY - Ya.I. Fedoniuk 2010

ANATOMY, PHYSIOLOGY, PATHOLOGY

CHAPTER 2. THE MUSCULOSKELETAL SYSTEM (THE MECHANICS OF MOVEMENT)

PATHOLOGY OF THE MUSCULOSKELETAL SYSTEM

DISORDERS OF THE MUSCULOSKELETAL SYSTEM

3. OSTEOPOROSIS. OSTEOPENIC CONDITIONS

Osteoporosis is a skeletal disorder characterized by an imbalance between Bone Formation and bone resorption, accompanied by bone rarefaction—that is, a decrease in bone mass per unit volume (density)—which leads to increased bone fragility.

The age-related decline in bone mass is a natural consequence of Aging; therefore, senile (age-related) osteoporosis is distinguished as a separate entity, frequently detected in individuals over 45 years of age and representing an almost universal sign of biological aging. In centenarians, osteoporosis is diagnosed in 100% of cases.

Furthermore, pathological bone loss is distinguished, occurring either without an apparent cause (primary, idiopathic osteoporosis) or secondary to other diseases (secondary osteoporosis). To date, the exact cause of bone resorption in osteoporosis remains unknown; however, numerous factors capable of triggering its development have been identified.

Osteoporosis may develop against the Background of other conditions (such as gastrointestinal disorders or endocrine dysfunctions), as well as due to the administration of certain medications (glucocorticoids, calcium channel blockers, oral contraceptives).

Osteoporosis is an extremely prevalent condition affecting approximately 210 million people worldwide. The issue of osteoporosis is highly relevant because early Diagnosis is only possible using specialized equipment—bone densitometers—which are far from available in all medical institutions. Another aspect of the osteoporosis problem of exceptional significance for Ukraine is post-radiation osteoporosis, the incidence of which has increased following the Chornobyl Nuclear Power Plant accident.

Osteoporosis should be differentiated from other osteopenic conditions.

Osteomalacia is a reduction in the mineral content of Bone tissue, leading to bone softening and skeletal deformity. Osteomalacia is observed in Rickets, a disease caused by Vitamin D deficiency that disrupts Mineral METABOLISM, primarily of Calcium and phosphorus. Rickets most frequently affects infants during their first year of life.

Osteolysis is the localized resorption of bone that is not accompanied by replacement with another tissue.

Osteodystrophy is a dystrophy of bone tissue caused by intraosseous Metabolic Disorders and characterized by the replacement of bone tissue with fibrous tissue or osteoid. Osteodysplasia refers to hereditary systemic skeletal disorders characterized by impaired or distorted bone morphogenesis. Manifestations of these conditions may include generalized defective bone formation, increased bone density due to excessive mineralization, or the presence of foci of underdeveloped, embryonic-like bone.

Osteonecrosis is the death of an area of bone tissue accompanied by the Separation and encapsulation of bone fragments with sequestrum formation, which is observed in inflammatory bone diseases (Various Forms of Osteomyelitis).