Elastic elements in the media and adventitia of human intracranial extracerebral arteries.

We find that the media and adventitia of adult human cerebral arteries contain elastic fibers forming a dense, coherent network, similar to that found in muscular arteries of the same size in other organs. The external elastic layer in the adult human is masked for the currently employed staining methods. By treatment with 90% formic acid before fixation, the original staining character of elastic tissue can be restored. The light microscopic and scanning electron microscopic features of this network of elastic fibers are presented.