Os penis of the rat. VI. Scanning electron microscopy of the surfaces of the mature bone.

Observations on the ultrastructural appearance of the surfaces of the mature os penis in the rat reveal that a majority of its surfaces may be classified as prolonged resting surfaces on very slow growing surfaces. Although a vast majority of the bone consists of bone tissue types which usually only form a small part of human and laboratory animal bones, their surface appearances resemble to a high degree surface appearances described for ordinary bone tissue types. Thus, surface morphology need not reflect tissue type variance. However, certain minor deviations from usual descriptions of surface appearances were observed. Such deviations are for instance the combination of partly mineralized fiber bundles and a fully mineralized amorphous ground substance on some of the observed surfaces. The combination may be a result of an extremely slow growth or a lost ability of the ageing bone forming cell to produce organized tissue.