Real mineral density of the sternum.

Mineral density of the sternum is insufficiently known. The aim of this research was to investigate mineralisation of the sternum and collect normative data on mineral density of the standard male and female sternum in elderly people (average age of female samples was 64 and male's was 62 years). The research was conducted on 93 cadaveric sternums, 56 male and 37 female samples. To determine regional mineral density of the sternum each sample was cut into six bony segments (Figure 1). Mineral density of every segment was determined using the method of ashing. Male sternums were on average denser than female ones in all segments. Average mineral density of the manubrium in women was 0.169 g/cm3 and 0.220 g/cm3 in men. Average mineral density of the body of the sternum also showed existence of sex difference; it was 0.160 g/cm3 in women and 0.227 g/cm3 in men. Both male and female sternums showed identical mineral density distribution. Mineral density of the manubrium and the body was roughly equal, while the analysis of longitudinal segments showed that the central part of both the manubrium and the body of the sternum was denser than lateral parts. Complex determination of the real mineral density for defined segments of the sternum and analysis of the obtained results were used to create the map of mineral density of the sternum in men and women (Figure 2). Maximum density values were four times greater than minimum density values for analysed samples. These data showed that osteoporosis also occurs on the sternum. Loss of structure and lower mineral density decrease the sternum quality and increase the risk of sternal dehiscence after median sternotomy.