Surely, many at least once thought about how many bones a person has. It is due to the presence of a large number of bones that people perform quite complex manipulations with the fingers, bend and unbend their body, and it is the bones that protect the internal organs from external influences. The skeleton of a newborn child consists of more than three hundred bones. However, as a person grows older, some bones grow together, so the number of bones in the body of an adult is approximately 206-208. Oddly enough it sounds, but to say for sure how many bones a person has is not possible.
When a person is born, his bones are quite soft, but over time they become harder and some of them grow together. For example, on the skull of a baby there are so-called fontanelles - places where connective tissue is present, which will subsequently be replaced by bone tissue. Later, at the site of the fontanel, the bones are fused, and this place becomes barely distinguishable. About how many bones a person has, different sources indicate different information, but we can say for sure that there are more than two hundred of them.
According to the degree of hardness, human bones are sometimes compared with steel, but they are much lighter due to their porous structure. Bone tissue is formed from cells and intercellular substance, which is rich in mineral components. Outside, each bone is covered with a periosteum, which, in turn, is pierced by numerous blood vessels that feed the bone. The structure of human bones is such that they are absolutely insensitive, nerve endings are found only in the periosteum. In childhood, the advantage in bone tissue of organic substances gives bones elasticity and resilience. In older people, and especially in the elderly, the predominance of inorganic substances causes bone fragility.
The structure of the bones , as well as their shape, are very different. In the human body there are flat bones, tubular and mixed, as well as air bones. The tubular bones are usually classified as long (femur and humerus, lower legs, bones of the forearm) and short (bones of the metatarsus, metacarpus, phalanx of the fingers). The relief of the bones, as well as their shape, directly depends on the method of attachment of muscle tissue to them. If the muscle connects to the bone tissue using tendons, a crest, tubercle or process is formed at the junction. If muscle tissue is combined directly with the periosteum, then a depression forms at the junction.
Bone marrow is located inside the bone, in the cells of the spongy substance and the bone marrow cavity. In newborns, all bones of the skeleton contain red bone marrow, which performs protective and hematopoietic functions. It is a network of special reticular fibers and cells. In adults, red bone marrow contains only spongy cells of flat bones. In the bone marrow cavities of the tubular bones, there is a yellow bone marrow, which is represented by a degenerated reticular stroma with fatty inclusions.
The thickest bone in the human body is the femur. It is extremely difficult to break, but a fracture of this bone can lead to quite serious consequences. An artery is located next to the femur, if damaged, a person can lose a lot of blood.
It is really difficult to say how many bones a person has. Different people have different numbers of bones. For example, some have extra ribs, while others have a sixth finger. About one out of twenty people has an additional rib, which is interesting - in men, the presence of an extra rib is more common than in the fair sex. Some people have several extra bones located in the arches of the feet.