This article has been cited by other articles in PMC. Abstract Background The prevalence of osteoporosis with related fragility fractures has increased during the last decades. As physical activity influences the skeleton in a beneficial way, exercise may hypothetically be used as a prophylactic tool against osteoporosis. Objective This review evaluates if exercise-induced skeletal benefits achieved during growth remain in a long-term perspective.
Low bone mass is thus visualized as a risk factor for fracture. According to recent World Health Organization WHO criteria, the term osteoporosis is also used to designate a bone mass value more than 2. Recognition of both sides of this ambivalent definition is important, because, ultimately, the pathophysiology of osteoporosis involves the development of not only low bone mass but of both the other skeletal components of fragility and the extraskeletal factors that lead to fracture.
The interplay of the multiplicity of these pathogenetic mechanisms is illustrated in Figure 1which situates the more important groups of causal factors relative to the undesired outcome, fracture.
A consequence of this multifactorial pathophysiology is the realization that a comprehensive approach to prevention must be multifaceted. Before beginning a systematic survey of pathogenetic factors, it is useful to examine the relative importance of mass and nonmass factors. Although mass is frequently considered to be the most important determinant of fragility, this is probably not correct.
Simulations suggest that mass explains less than half of the observed fracture risk, 14 and clinical studies have demonstrated that expressed fragility e. Figure 2 illustrates their aggregate importance. Age-specific fracture risk gradients are presented for various values of forearm bone mineral density BMD.
Three features stand out: As Figure 2 also shows, the age effect is actually larger than the bone mass effect. Age, of course, is a surrogate for a multiplicity of factors.
These include the tendency to fall more often; slow postural reflexes which cause a person to fall in such a way as to strike vulnerable bony parts e. Several of the other articles in this issue deal with the treatment of low bone mass or the prevention of bone loss.
Bone mass, as already noted, is but one of the factors contributing to osteoporosis. Although the primary focus of this article is on pathophysiology, a discussion of preventive approaches for nonmass pathogenetic factors is also included.
Previous article in issue Recommended articles Citing articles 0 Address reprint requests to Robert P. Heaney, MD, N. Published by Elsevier Inc.Osteoporosis is a systemic skeletal disease manifested by reduced bone strength, decreased bone mineral density (BMD), and altered macrogeometry and .
With osteoporosis, there is reduced bone density and structure in the spongy bone, as well as thinning of the cortical bone. When your bones have thinned to the point that osteoporosis is diagnosed, the physical structure — . Structure And Functions Of The Skeletal System Words | 6 Pages TASK 1- Skeletal system Produce an information project that can be displayed around a sports club or for athletes to give information on the different structures and functions of the skeletal system.
Osteoporosis, or porous bone, is a disease characterized by low bone mass and structural deterioration of bone tissue, leading to bone fragility and an increased risk of fractures of the hip, spine, and wrist.
Osteoporosis is defined elsewhere in this issue as a condition of skeletal fragility characterized by reduced bone mass and microarchitectural deterioration of bone tissue with a consequent increase in risk of fracture. Osteoporosis makes bones thinner and weaker, making them break more easily.
Bone is constantly undergoing a process called remodelling, where old bone is broken down and new bone is built up again. Osteoclasts (a type of cell found in bone) cut out old bone and release calcium phosphate into the blood, osteoblasts (other cells) build up new bone .