The star volume is a new stereologic parameter which can describe structural changes of trabecular bone. It is defined as the mean volume of all the parts of an object which can be seen unobscured in all directions from a particular point inside the object. The mean is over all points inside the object. The parameter is only unbiased when Baddeley’s vertical or isotropic sections are used.

The star volume of the marrow space (V*_m.space) and of the trabeculae (V*_tr) was estimated on vertical sections obtained from the first lumbar vertebra and the iliac crest. The continued autopsy material presented was from 7 females and 11 males without malignant or metabolic bone diseases. The mean age was 52 years (range 7-87 years).

The sampling procedure was as required for vertical sections and an anisotropic test system was used.

A significant age-related increase was shown in marrow space star volume in both lumbar vertebra and iliac crest. The increase in lumbar vertebra marrow space star volume was significantly greater for women than for men. Moreover, a significant correlation was found between the marrow space star volume in lumbar vertebra and iliac crest (r = 0.72, 2p < 0.01). No such relation was found for trabecular star volume which did not change with age.

The results also revealed that marrow space star volume could be measured on conventional bone biopsies preferably, however, on two mutually perpendicular vertical section planes.