Compact vs Spongy: Difference and Comparison

Bones constitute the primary skeletal structure of the human body that supports the muscles and gives shape to the body. Compact and spongy are the two basic types of structural bones.

These bones help in making the long bones in the body. The long bones are dense and hard bones that provide strength, structure and mobility to the body.

Key Takeaways

1. Compact bone is dense and forms the outer layer of bones, while the spongy bone is porous and fills the inner layer.
2. Compact bone provides strength, while spongy bone supports and protects internal organs.
3. Compact bone has few spaces, while spongy bone contains numerous spaces containing bone marrow and blood vessels.

Compact vs Spongy

Compact means something which is very tightly closed together having a bulky shape. A compact thing is well organized and compressed. Spongy refers to something mushy and well absorbing. Spongy things have pores and airy surfaces.

Comparison Table

Parameters of Comparison	Compact	Spongy
Definition	Compact bone tissues are made up of osteons and construct the bones’ external layer.	Spongy bone tissues comprise trabeculae, which construct the bones’ inner part.
Another name	Another name is cortical bones.	Another name is cancellous or trabecular bones.
Nature	They are heavy and compact.	They are light, spongy and soft.
Bone Marrow Cavity	The bone marrow cavity is present in the centre.	The bone marrow cavity is absent.
Area	They fill the outer layer of most of the bones.	They fill the inner layer of most of the bones.
Made of	They are made up of osteons.	They are made up of trabeculae.
Forms	They construct the shaft or the diaphysis of the long bones.	They construct the ends or the epiphyses of the long bones.
Work	Bone marrow stores the fat molecules.	Bone marrow produces the red corpuscles and the white granular corpuscles.

What is Compact?

Compact bone tissue is the cancellous portion of the bone made up of osteons and constructs the external layer of the human bones. Another name for them is cortical bones. They have a high amount of calcium content available in them.

The compact bone tissues have a cylindrical shape and are hard. They do not contain spaces between the lamellae.

They have the bone marrow cavity present in them. They contain yellow-coloured bone marrow and can take up to 80% weight of the skeleton.

The compact bone tissues can be found in the inner surface of the bone and construct the major part of the long bones, like the arms and the legs. They help provide structural support to the body and can also handle weights up to 5000 pounds.

What is Spongy?

Spongy bone tissue is the bony tissue of trabeculae and constructs the inner part of the bones. Another name for them is cancellous or the trabecular bones.

They lack the presence of the bone marrow cavity and contain red-coloured bone marrow.

Spongy bone tissues are made up of trabeculae and have a cuboidal shape. It fills the inner cavity of the bones, which consists of the mineralized bars called the trabeculae. They contain spaces between the lamellae.

Spongy bone tissues are soft and porous. They can take around 20% weight of the skeleton. They cannot handle heavier weights. They have a very low calcium content present in them.

Spongy bone tissues construct the major part of short bones, like the wrists and the ankles. They are present in the bone’s outer layers and are a buffer to compact bone tissues.

Main Differences Between Compact and Spongy

1. Compact bone tissue is the cancellous part of the bone that constructs the external layer in the bones. On the other hand, spongy bone tissue is the bony tissue that constructs the inner part of the bones.
2. Compact bone tissues have another name, cortical bones. On the other hand, spongy bone tissues have another name, cancellous or trabecular bones.
3. Compact bone tissues are made up of osteons. On the other hand, spongy bone tissues are made up of trabeculae.
4. Compact bone tissues have a bone marrow cavity present in them. On the other hand, spongy bone tissues do not have a bone marrow cavity present in them.
5. Compact bone tissues do not contain spaces between the lamellae. On the other hand, spongy bone tissues contain spaces between the lamellae.
6. Compact bone tissues have a cylindrical shape. On the other hand, spongy bone tissues have a cuboidal shape.
7. Compact bone tissues are hard. On the other hand, spongy bone tissues are soft and porous.
8. Compact bone tissues contain high content of calcium present in them. On the other hand, spongy bone tissues contain high content of calcium present in them.
9. Compact bone tissues can take 80% weight of the skeleton. On the other hand, spongy bone tissues can take 20% weight of the skeleton.
10. Bone marrow in compact bone tissues can store fat molecules, whereas bone marrow in spongy bone tissues produces red and white granular corpuscles.
11. Compact bone tissues contain yellow bone marrow. On the other hand, spongy bone tissues contain red bone marrow.
12. Compact bone tissues construct the major portion of long bones, like the arms and the legs. On the other hand, spongy bone tissues construct the major portion of short bones, like the wrists and the ankles.
13. Compact bone tissues are present in the inner part of the bone, whereas spongy bone tissues are present in the outer part of the bone.
14. Compact bone tissues can support weights up to 5000 pounds, whereas spongy bone tissues cannot support heavy weights.
15. Compact bone tissues help in providing structural support to the body. On the other hand, spongy bone tissues behave as a buffer to compact bone tissues.

References

1. https://www.karger.com/Article/Abstract/146337
2. https://iris.unimore.it/handle/11380/638220