Recognition and significance of pulmonary bone embolism.

Embolism of bone marrow to the lungs is a quite frequent finding after trauma but transport and deposition of solid bone is rarely seen, which may simply be because pulmonary calcifications are not recognized as bone fragments. We report on three patients with embolism of bone spicules to small lung arteries of about 0.5 mm in diameter which were plentiful in two of the patients on postmortem examination. However, the true nature of the emboli was only recognizable after decalcification of lung tissues. It appears that trauma occurring in a septic bone lesion has the greatest chance to provoke bone embolism. The bone spicules do not usually occlude vessel lumina and thus do not severely disturb the blood circulation in the lungs. The bone fragments become covered by endothelium and can remain recognizable for months or even years.