Grafting of the Bone

| - osteoblasts begin to replace the fibrocartilage splint with spongy and compact bone, forming a bulge that is initially wider than the original bony shaft

Bone remodeling This is where the body replaces old bone with new bone. The woven bone is replaced by lamellar bone. Osteoclasts remove small bone fragments and osteoblasts deposit spongy bone, converting it to compact

Longitudinal bone growth occurs at the epiphyseal plate, which is a thin layer of cartilage between the epiphyseal and metaphyseal bone at the distal ends of the long bones. Bone growth is the result of maturation, growth of chondrocytes, their production of bone matrix, and finally calcification (47). The growth plate is a complex structure consisting of different layers of cells, as shown in figure 3. The most immature cells, the stem cells, are found towards the epiphyseal end of the growth plate in the stem cell zone, or resting zone; the proliferating zone contains more mature chondrocytes and the hypertrophic zone contains the larger chondrocytes. The resting stem cells in the resting zone are recruited, whereupon proliferation and differentiation

Bone is a living tissue and made up of cartilage. Fibrodysplasia ossificans progressiva bone appears as normal bone tissue, but it develops in the wrong places. Osteogenesis and ossification are medical terms which refer to the formation of bone. Most bones in the human body grow and heal up after a break through endochondral bone formation, which is how FOP bones grow. Cartilage forms first and then the bone will eventually take the place of cartilage.

Bone Development and Growth. The term ossification refers to the formation of bone. The bones of the skeleton form during embryonic development in two distinctive ways: intramembranous ossification and endochondral ossification.

Bone is surrounded by a thin membranous layer of soft tissue called periosteum (Singh, 2017). When the bone breaks it bleeds from torn ends because of the disruption of the supplying blood vessels. And quite naturally the periosteum is also torn. A fracture hematoma forms and white blood cells march in to clean up the area that is injured. The periosteum is the primary source of osteoblasts, which plays a huge role in fracture healing (Singh, 2017). After the hematoma formation, the next step is callous formation with the formation of cartilage and bone and then the remodeling phase consisting of the osteoclasts and the osteoblasts reshaping the bone to its original state (Patton, 2012).

What are the roles of osteoclasts in bone formation? Osteoclasts are large cells that function to reabsorb, or to digest bone tissue. They digest bone tissue from the inner sides of bones thus enlarging the inner bone cavity so that the bone does not become overly thick and heavy.

When a bone is broken the following things happen: a blood clot forms around the break. Inside the blood clot, special cells called phagocytes begin cleaning bone fragments and killing any germs which might have gotten in around the break. Phagocytes are part of the immune system. Next, a soft callus made mostly of collagen is created around the fracture by another special group of cells called chondroblasts. This stage can last anywhere from 4 days to 3 weeks. A hard callus forms next as osteoblast cells create new bone, adding minerals to make it hard. This stage typically begins 2 weeks after the break, and ends somewhere between the 6th and 12th week. Lastly, the bone is remodeled. Special cells called osteoclasts break down extra bone around the fracture until it's completely healed and returned to its original shape. This stage typically begins 2 weeks after the break, and ends somewhere between the 6th and 12th

* Guide To Using The Bone Mechanics Series. (n.d.). The Biomechanics of Bone Tissue Part I by Jacob Wilson. Retrieved from http://www.abcbodybuilding.com/magazine03/bonemechanics1.htm

Ossification and osteogenesis are synonyms meaning the process of bone formation. In embryos this process leads to the formation of the bony skeleton. As a person grows, another form of ossification known as bone growth goes on until early adulthood as the body continues to increase in size. Bones are capable of growing in thickness throughout life.

There are 206 bones in the human body. Broken and fractured bones are one of the most common injuries, about 6 million people in the US will break a bone each year. And out of these 300,000 people will have a serious injury that will require different methods to heal. There are a variety ways of bone tissue repairing but most of them are not long term and can cause other complications. There are different stages for bone repair. The first step is the formation of hematoma at the break, then the formation of a fibrocartilaginous callus, the third step is the formation of a bony callus, and finally remodeling and addition of compact bone. In the early stages, a hematoma develops within the fracture location during the first few hours and days.

Bones are joined together by joints, most of which authorize movement between the bones. Additionally, bones are a form of connective tissues manufactured by osteoblasts, which signifies immature bone cells. Speaking of bone formation, ossification occurs in two ways. One being is endochondral ossification which is established within cartilage, is the most common way the majority of bones form. Secondly, intramembranous ossification structures the flat bones of the skull, clavicle, and mandible. Furthermore, the skeletal system manufactures blood cells, which the process is named hematopoiesis, and archives and exports

The natural process of healing a fracture starts when the injured bone and surrounding tissues bleed, forming a fracture hematoma. The blood coagulates to form a blood clot situated between the broken fragments. Within a few days, blood vessels grow into the jelly-like matrix of the blood clot. The new blood vessels bring phagocytes to the area, which gradually remove the non-viable material. The blood vessels also bring fibroblasts in the walls of the vessels and these multiply and produce collagen fibres. In this way the blood clot is replaced by a matrix of collagen. Collagen's rubbery consistency allows bone fragments to move only a small amount unless severe or persistent force is applied.

The main difference between intramembranous and intracartilaginous bone formation are the primary structure from which ossification initiates and the method of bone growth. Intramembranous bone formation commences with the development of a membrane in the area of the bone to be formed. The embryonic mesenchymal cells that make up the membrane develop osteogenic cells and then osteoblasts to allow layers of bone tissue to form in the shape of the membrane. The flat bones covering the brain and some facial bones maintain a constant thickness level to allow for brain growth. As they enlarge, new bone tissue is built and removed to the internal and external surfaces and along the margins.

From the background provided on trabecular bone biology and tissue properties, the major highlights included: cell populations, mechanosensation, mechanotransduction, tissue composition, and tissue elastic properties. In the cellular matrix of trabecular bone, three main multicellular units, osteoclasts, osteoblasts and osteocytes, exist. Osteoclasts function in bone resorption as part of the bone remodeling process.