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, grow together in a monolithic formation and harden. The epiphyseal plate is responsible for one of the main features of the bones - their rapid growth in length. So tubular long bones — arms and legs — grow.
How does the bone of a newborn turn into a mature, hardened bone of an adult? This process occurs inside the young cartilage and is called ossification. Due to the structure of the cartilage, the bones of children are very flexible, and in case of a fracture they quickly coalesce. But already in adolescence, the area of growth is noticeably reduced
Epiphyseal Cartilage Function in the Bone
In children, the bone is updated very quickly. First, the bone tissue has a mesh structure, then it is replaced by a lamellar structure with secondary haversian structures. From birth to the puberty, bones grow rapidly due to the special structure of the epiphyseal cartilage.
This cartilage is located between the diaphysis and the pineal gland. The pineal gland is the thickened articular surface of the bone, and the diaphysis is its long part. The cells of the epiphyseal region (growth zone) are divided in half and accumulate. Sites of ossification are gradually formed, which then grow together and form a firm and elastic bone - protection for the red bone marrow.
So there is a growth of tubular bones in length. The periosteum is responsible for the growth in width. Growth is 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 hormone or lack of calcium due to poor nutrition leads to the fact that the child grows slowly and grows quite low. But also the cause is sometimes heredity.
After the puberty, bone growth slows significantly. And until the age of 21, all large bones harden. Epiphyseal cartilage in the joints also harden; more precisely, they are replaced by hyaline cartilage, which provides cushioning and reduces friction during the contact of moving parts of the joint. Articular cartilage must be protected from a young age.
The growth zone, gradually shrinking, disappears almost completely. Small bones of the skeleton ossify by the age of 25 in men. In women, even to 22-23 years.
How does bone hardening occur?
During fetal development, a substance called mesenchyme forms in the fetus. After birth, it is replaced by cartilage, and then, gradually, the epiphyseal cartilage is replaced by mature bone tissue.
So, a child has a relatively soft structure between the diaphysis (bone body) and the pineal gland. 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, and those, 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 salts 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.
Is it possible to correct the bent legs of a child
Often children have a problem such as abnormal (crooked) bone growth. How can this be fixed? To do this, plates are placed in the epiphyseal cartilage 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, on both sides evenly.
Factors Affecting Bone Growth
There are several principles of bone growth that P.F. Lesgaft. We already know about the hormone, what else needs to be understood? So, in order for epiphyseal cartilage to grow rapidly, you need to eat a lot of calcium and magnesium with food. But bones also need physical activity:
- Bone development depends on muscle activity.
- And also bone formation 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 growth is formed.
- The shape of the bone depends on the external pressure exerted on it. Adolescents are recommended to hang on the horizontal bar more often, for example, to stimulate bone growth.
As we can see, the growth of epiphyseal cartilage depends on many factors. Do not think that it is due to 100% of the genes. Bone growth occurs at a certain level of stress. And the second condition - training should not be missed.
Cartilage osteomyelitis
Both children and adults sometimes have bone damage called osteomyelitis. This is an inflammatory disease. If the child is affected by an epiphyseal cartilage infection, then we are talking about epiphyseal osteomyelitis. In adults, this cartilaginous plate remains a little.
Inflammation occurs as a result of open fractures when an infection gets into the bone tissue. It can also develop for a long time near the bone in the soft tissues and gradually pass into the bone. In such cases, they speak of a secondary epiphyseal infection.
Fractures in bone growth in childhood
Epiphyseal cartilage damage accounts for 15% of all childhood fractures. And half of them occur in the elbow or forearm. More often, children injure the growth area while playing soccer, gymnastics or athletics.
If fractures occur in the area of bone growth in children, the prognosis is very good. Even if there is a fracture in the elbow or knee joint. The sites 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, severe pain may occur at the site of the overgrown fracture.
Output
What mechanism is responsible for bone growth? Due to this cartilage.
In children, the bone is still very flexible. Their epiphyseal cartilage still has few sites of ossification. The process of ossification, that is, the replacement of osteoblasts with osteocytes, lasts up to 25 years. The epiphyseal plate is the remainder of the elastic cartilaginous layer between the pineal gland and the diaphysis.