Biomedical Engineering Reference
In-Depth Information
1
Introduction
to Bone Materials
1.1 Introduction
Bone is a highly organized and specialized support tissue that is charac-
terized by its rigidity, porosity, and hardness. It is a connective tissue with
both cellular and extracellular matrix composed of extracellular fibers and
a dense crystalline material. Impregnated with inorganic salts, bone con-
tains mainly salts of calcium such as calcium phosphate, calcium carbonate,
etc. The inorganic portion occupies two-thirds of the bone and the organic
salt component constitutes the rest. Inorganic salts are mainly responsible
for the rigidity and hardness that allow bone to resist compression caused
by the forces of weight and impact. The organic connective tissue of bone
makes it resilient, thus affording resistance to tensile forces. Bones support
and protect various organs of the body, produce red and white blood cells,
and store minerals.
1.2 Types of Bones
Living bones are classified on different bases. Generally, five types of clas-
sification are used. They are based on a macroscopic approach, microscopic
observation, geometric shape, patterns of development, and the regions in
which bones are located. In this section, we present a brief review of the
first three classifications. The remaining two types, which are not commonly
used, are listed in Appendix A for readers' convenience.
1.2.1 Bone Types Based on the Macroscopic Approach
From the viewpoint of bone macrostructure there are two primary types of
bone: compact bone and spongy bone.
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