Basic Medical Sciences

There are different basis on which bones can be classified. The bones might be classified on the basis of shape or on the basis of development or on the basis of the region where they exist or finally on the basis of structure. In order to get adequate knowledge of classification of bones it is good to understand all the basis of classification and the corresponding types of bones.

Classification of bones on the basis of shape: On the base of shape the bones can be classified into the following types;

Long bones: These bones are long in composure and are of further three types that are typical long bones, miniature long bones and the modified long bones. The typical long bones are represented by bones of the limbs such as humerus, ulna, radius etc. The miniature long bones are represented by the bones of the phalanges. The modified long bones are represented by the clavicle.

Short bones: These bones are of short composure and usually have specified shapes according to which they are named. The examples are the scaphoid, lunate, pisiform etc which are all carpal bones.

Flat bones: These bones have a flat composure resembling shallow plates. Example is the scapula bone.

Irregular bones: These bones are irregular in shape such as the vertebral bones.

Pneumatic bones: These are the bones which contain air spaces in them such as the maxilla bone.

Classification on the basis of development: On the basis of development the bones are classified into the following types;

Dermal bones: They are also known as membrane bones. These bones ossify in membrane (mesenchymal ossification). Examples of this category of bones are facial bones.

Cartilaginous bones: Cartilaginous bones ossify from an already present cartilage model (endochondral ossification). The examples of this category of bones are bones of the limbs.

Membro-cartilaginous bones: These bones ossify partly in membrane and partly in cartilage. Example of this type of bone is clavicle.

Classification on the basis of region: On the basis of region the bones are of the following types;

Bones of axial skeleton: These are the bones forming the parts of the axial skeleton of the body. Examples are the bones of skull and vertebral column.

Bones of the appendicular skeleton: These are the bone which forms the appendages for example bones of the upper limb.

Classification on the basis of structure: On the basis of structure on which the bones are made, there are the following types;

Compact bone: The type of bone or the part of bone where the bone substance to bone spaces ratio is large is known as the compact bone.

Spongy bone: The type of bone of the part of bone where the bone substance to bone spaces ration is small is known as the spongy bone