Bone Cortical And Cancellous
Introduction[edit | edit source]
Bones are divided into two macroscopic forms: cancellous bones (aka spongy or trabecular bone) and cortical bones (or compact bone). Cortical bones make up most of the skeletal system (up to 80%), while the rest is cancellous bones (roughly 20%).
Lamellae Difference: The extracellular matrix of bone is composed mainly of type 1 collagen, these fibers adopting a preferential orientation in the human skeleton, resulting in the formation of lamellar bone (a thin layer of bone).
- In cortical bone, these lamellae are arranged concentrically around the Haversian systems
- In cancellous bone, they are parallel to one another.
Cancellous Bone[edit | edit source]
Cancellous bone is located in the medullary cavity of bone of tubular and short bones. It consists of dense trabeculae (struts), that traverse the bone marrow-filled medullary cavity, and are geometrically arranged to withstand local forces transmitted through the bone and are modifiable.
- This bone has high porosity (> 70–80%) with more space than compact bone. The high surface area facilitates cancellous bone which have a higher metabolic activity compared to cortical bone, eg bone cell production and mineral exchange is higher in trabecular bone compared to cortical bone.
- The bone marrow of cancellous bones produces red blood corpuscles and white granular corpuscles.
- Although cortical bone is thought to bear the majority of the load in an individual bone, cancellous bone does contribute and serves to load share stresses out to the cortex.
- Microscopically it is identical to cortical bone.
Cortical Bone[edit | edit source]
Cortical bone forms a protective layer around the internal cavity. Cortical bones high resistance to bending and torsion, making them able to bear the weight of the body.
The key function of a cortical bone is in providing strength and protection to bones. Cortical bone is fairly smooth in comparison to a cancellous bone. The structure of the cortical bone consists of many layers.
- The most outside layer of the cortical bone is the periosteum, a two-layered structure. It serves to protects the nerves and blood vessels that run through the cortical bone. The interior layer of the periosteum consists of osteoblasts, which synthesize bone matrix.
- A bone marrow cavity is located in the centre of cortical bones, which stores fat.
Links[edit | edit source]
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References[edit | edit source]
- Radiopedia Cancellous bone Available:https://radiopaedia.org/articles/cancellous-bone (accessed 12.11.2022)_
- Science direct Cortical bone Available:https://www.sciencedirect.com/topics/medicine-and-dentistry/cortical-bone (accessed 12.11.2022)
- Difference between.com What is the Difference Between Cancellous and Cortical Bone Available:https://www.differencebetween.com/what-is-the-difference-between-cancellous-and-cortical-bone/ (accessed 12.11.2022)
- Encyclopedia of Bone Biology Available:https://www.sciencedirect.com/referencework/9780128140826/encyclopedia-of-bone-biology (accessed 12.11.2022)