The so-called "brush" consists of a number of parallel, membranous tubules made of globular calcified cartilage and is covered in a thin, acellular bone layer.
The so-called "brush" is not fibrous as was originally believed, but consists of a number of parallel, membranous tubules made of globular calcified cartilage. The brush base and basal plate are covered in a thin, acellular bone layer.