Age-related structural changes in trabecular and cortical bone: Cellular mechanisms and biomechanical consequences

Abstract

It is proposed that there are two structurally different forms of bone loss with different rates, cellular mechanisms, and biomechanical effects. Rapid bone loss is the result of excessive depth of osteoclastic resorption cavities. This leads in trabecular bone to perforation of structural elements, increased size of marrow cavities, and discontinuity of the bone structure, and in cortical bone to subendosteal cavitation and conversion of the inner third of the cortex to a trabecularlike structure, which then undergoes the same changes as the trabecular bone originally present. These structural characteristics reduce the strength of the bones to a greater extent than the reduction in the amount of bone by itself would suggest. Slow bone loss results from incomplete refilling by osteoblasts of resorption cavities of normal or reduced size. This leads to simple thinning of residual structural elements in both trabecular and cortical bone, and reduces the strength of the bones in proportion to the reduction in the amount of bone. This concept, although derived mainly from an examination of postmenopausal bone loss, may be applicable to other osteopenic states. At the same time as bone loss is occurring on the endosteal surface, rapidly or slowly, bone is being added to the periosteal surface, but much more slowly than during growth. The cellular mechanism is the converse of that causing slow bone loss, consisting of slight overfilling of shallow resorption cavities. Slow periosteal gain serves to partly offset the structural weakness resulting from endosteal loss, but is not directly compensatory.(ABSTRACT TRUNCATED AT 250 WORDS)

Forensic age estimation based on the trabecular bone changes of the pelvic bone using post-mortem CT

“…The structure of the trabecular bone changes with increasing age due to the imbalance of the processes of bone remodeling: consequently, the bone density decreases, the trabeculae lose their interconnection until they disappear, and therefore the medullar space increases [9], [10]. The first radiographic investigations of the trabecular bone were performed by Todd [11] who analyzed the pubic bone.…”

Bone histomorphometry of broilers submitted to different phosphorus sources in growing and finisher rations

“…There is little information about systematic use of quantitative image analysis methodologies in those recent works. The study of cortical bone in undermineralized histological slides can contribute to address, in a systematic and objective way, the importance of organic matrix geometry to the bone strength and biomechanical properties (Parfitt, 1984;Rath et al, 1999).…”

A comparison of the microarchitecture of lower limb long bones between some animal models and humans: a review

“…However, it was shown that in rats cancellous bone tissue occupies a proportionally smaller area than in humans (Bagi et al 1997). Despite this, humans have more cancellous bone tissue which increases the total strength of the femur and acts like a load conductor, allowing bipedal locomotion (Wolff 1892;Pugh et al 1973;Martens et al 1983;Parfitt 1984Parfitt 1987. In addition, humans have two kinds of cancellous bone tissue: peripheral and central part of the cancellous bone.…”