Assessment of cortical and trabecular bone distribution in the beagle skeleton by neutron activation analysis

Abstract

The distribution of bone calcium between morphologically identifiable cortical and trabecular bone obtained by dissection and quantitated by neutron activation analysis (NAA) is described. The skeleton of a female beagle dog was dissected into approximately 400 pieces and assayed for 49Ca produced in the University of California, Irvine TRIGA reactor. For each of the skeletal sections, we give the initial weight of the alcohol-fixed tissue, which includes cortical bone, trabecular bone, marrow, and cartilage, and a final tissue weight after the marrow and trabecular bone have been dissected away; total section and cortical section calcium weights are reported. The level of detail is represented, for example, by the vertebrae, which were divided into three parts (body, spine, and transverse processes) and by the long bones, which were divided into 10-12 parts such that characterization of the epiphysis, metaphysis, and diaphysis was accomplished. The median percentage cortical calcium values for cervical, thoracic, and lumbar vertebrae were 82%, 56%, and 66%, respectively; however, variation within these groups and among individual vertebral sections was about a factor of 2. For long bones, the median percentage cortical calcium varied from 90-100% in the midshaft to below 50% in the proximal and distal sections. The final calculated cortical tissue-to-calcium mass ratio (TCR) varied from about 4.5 for midshafts of the long bones to about 9 for thoracic vertebral bodies and indicated that the mineral fraction of cortical bone is not constant throughout the skeleton. The ratio of cortical to trabecular calcium in the skeleton was 79.6:20.4.

On age-related mammalian bone loss: Insights of the Utah paradigm

“…During that age span cortical porosity in healthy ribs increases about 4 % , from about 3 % to 7 % (14). Simultaneously sluggish formation drifts increase outside bone diameter by about 5 % , which adds about 10% (1.05 2 ) to the original young-adult compacta (23,49,51,53) (compacta provides about 80% of the global adult bone bank [41]). Without any age-related bone loss, and ignoring spongiosa, that 10% cortical bone bank increase would provide a global bone bank at 75 years of age of about 110% of the young-adult bone bank.…”

Rapid determination of cancellous bone mineral loss in ovariectomized rats by a subtraction technique

“…It seems straightforward. All techniques for determining cancellous bone mineral in small animals must rely on anatomic dissection and separation of cancellous and cortical bone (Nottestad et al, 1987;Gong et al, 1964;Parks et al, 1986;Gunness-Hey and Hock, 1984). However, most require saving the marrow and small pieces of removed cancellous bone so that they can be evaluated.…”