Bones are plastic formations, especially in early childhood. Their cells - osteocytes are able to divide in half and grow stronger. Some bones consist of several parts, and then, with age, coalesce into a monolithic formation and harden. The epiphyseal plate is responsible for one of the main features of the bones - their rapid growth in length. This is how tubular long bones grow - arms and legs.
How does the bone of a newborn develop into mature, hardened bone of an adult? This process occurs within young cartilage tissue and is called ossification. Due to the structure of the cartilage, the bones of children are very flexible, and in the event of a fracture, they quickly fuse. But already in adolescence, the growth area is noticeably reduced
Functions of the epiphyseal cartilage in bone
Children's bone is renewed very quickly. At first, the bone tissue has a mesh structure, then it is replaced by a lamellar one with secondary Haversian structures. From birth to puberty, bones quicklygrow due to the special structure of the epiphyseal cartilage.
This cartilage is located between the diaphysis and the epiphysis. The epiphysis is the thickened articular surface of the bone, and the diaphysis is its long part. The cells of the epiphyseal region (growth zone) divide in half and accumulate. Gradually, areas of ossification are formed, which then grow together and form a hard and elastic bone - protection for the red bone marrow.
This is how tubular bones grow in length. The periosteum is responsible for the growth in width. Growth occurs due to the hormone somatotropin. It is produced by the pituitary gland. In addition to growth hormone, some other substances are also needed for growth - insulin and thyroid hormones.
Lack of a hormone or lack of calcium due to poor nutrition leads to the fact that the child grows slowly and grows quite short. But sometimes heredity is also the cause.
After puberty, bone tissue growth slows down significantly. And before the age of 21, all large bones harden. The epiphyseal cartilages in the joints also harden; rather, they are replaced by hyaline cartilage, which provides shock absorption and reduces friction during contact of the moving parts of the joint. Articular cartilage needs to be protected from a very young age.
The growth zone, gradually shrinking, disappears almost completely. The small bones of the skeleton ossify by the age of 25 in men. In women, even by the age of 22-23.
How does bone harden?
During the periodIn utero, the fetus develops a substance called mesenchyme. After birth, it is replaced by cartilage, and then, gradually, the epiphyseal cartilage is replaced by mature bone tissue.
So, the child has a relatively soft structure between the diaphysis (the body of the bone) and the epiphysis. This is epiphyseal cartilage. During the active growth of the child, the process of primary and then secondary ossification occurs. This means that chondrocytes (cartilage cells) are replaced by osteoblasts, which in turn are replaced by osteocytes.
Osteoblast cells actively produce intercellular substance, and then calcify and turn into osteocytes. Osteoblasts are young bone cells; they help debug calcium s alts in the bone matrix. And osteocytes are already hardened mature cells. Cartilage tissue in the process of calcification of osteoblasts slowly dissolves. Thus, the epiphyseal cartilage turns into the bone of an adult.
Can a child's crooked legs be corrected
Often children have such a problem as incorrect (crooked) growth of bone tissue. How can this be fixed? To do this, plates are placed in the epiphyseal cartilages of both legs on one side of the cartilage. Due to their growth continues only on one side, and after a few years the bones in the child are aligned due to the correction of the angle.
Closer to 13-14 years, the plates are removed so that further growth continues unhindered, evenly on both sides.
Factors affecting bone growth
There are several principles of bone growthfabrics that P. F. Lesgaft. We already know about the work of the hormone, what else needs to be understood? So, in order for the epiphyseal cartilage to grow rapidly, it is necessary to consume a lot of calcium and magnesium with food. But bones also need exercise:
- Bone development depends on muscle activity.
- And also the formation of bone depends on the processes of tension and compression. It is known that in the place where the muscle is attached by the tendon to the bone, a bone outgrowth is formed.
- The shape of the bone depends on the external pressure exerted on it. Teenagers are advised to hang on the horizontal bar more often, for example, to stimulate bone growth.
As we can see, the growth of the epiphyseal cartilage depends on many factors. Do not think that it is 100% due to genes. Bone growth occurs at a certain level of stress. And the second condition is that training cannot be missed.
Osteomyelitis of cartilage
Both children and adults sometimes have a bone lesion called osteomyelitis. This is an inflammatory disease. If a child has an infection of the epiphyseal cartilage, then we are talking about epiphyseal osteomyelitis. In adults, this cartilage plate remains a little.
Inflammation occurs due to open fractures, when an infection enters the bone tissue. It can also develop for a long time next to the bone in the soft tissues and gradually move into the bone. In such cases, they speak of a secondary epiphyseal infection.
Fractures in the area of bone growth in childhood
Epiphyseal cartilage damage accounts for 15% of all childhood fractures. Andhalf of them occur in the elbow or forearm. More often children injure the growth zone while playing football, gymnastics or athletics.
If fractures occur in the area of bone growth in children, then the prognosis is very good. Even if the fracture is in the elbow or knee joint. The patches grow surprisingly fast. But in a teenager, the epiphyseal cartilage in the joint is already a partially ossified structure, and all elements of the joint must be clearly restored. Otherwise, in adulthood, there may be severe pain at the site of an overgrown fracture.
Conclusion
Due to what mechanism does bone growth occur? Due to this cartilage tissue.
Children's bones are still very flexible. Their epiphyseal cartilage still has few areas of ossification. The process of ossification, that is, the replacement of osteoblasts with osteocytes, lasts up to 25 years. The epiphyseal plate is the remnant of the elastic cartilage layer between the epiphysis and the diaphysis.
