Classification of Bones Anatomy

Skeletal System

The skeletal system is made up of bones and cartilage. It provides a strong and flexible framework for the body.

Bones

Question 1. What is bone?
Answer.

The bone is a specialized connective tissue with a mineralized matrix of calcium salts, for example, calcium hydroxyapatite crystals. It provides hardness to the human skeleton.

Classify bones according to their shape.

Classification of Bones

1. Long bones: They consist of a shaft and two ends. The elongated tubular shaft or body is called diaphysis. It contains a medullary cavity within it. The expanded ends are called epiphyses. Examples: Long bones of limbs such as femur, tibia and fibula in the lower limb and humerus, radius and ulna in the upper limb.
2. Short long bones (also called miniature long bones): They have a shaft and only one epiphysis. Examples: Metatarsals, metacarpals and phalanges.
3. Short bones: They are smaller in size and usually cube-shaped. Examples: Carpal and tarsal bones.
4. Flat bones: They are flat (plate-like) and consist of two layers (plates) of compact bone with spongy bone, filled with bone marrow between them. Examples: Bones forming the skull cap such as frontal, parietal and occipital. The ribs, sternum and scapula are also classified as flat bones.
5. Irregular bones: They have an irregular shape. Examples: Bones of the face and base of the skull; vertebrae and hip bones.
6. Pneumatic bones: They contain cavities within them, which are filled with air. These bones are confined to the skull. Examples: Paranasal bones such as maxilla, ethmoid, sphenoid and frontal bones.
7. Accessory bones: They are sometimes present in the limbs and skull. Examples: Os trigonum (os vesalianum), os cubiti in the limbs and wormian bones in the skull.
8. Sesamoid bones: They develop in the tendons of muscles and are devoid of periosteum. Examples: Patella and fabella.