From the article you will learn about the structural features of the skeleton of the head. The fact is that some bones of the brain skull are significantly different in structure from the facial. How does this affect their functions? Let's figure it out together.
Anatomical characteristics of the human skull
The skeleton of the head, or skull, consists of 27 bones. It also includes a malleus, stapes and anvil. These are the auditory ossicles that are located in the middle ear cavity. As part of the sensory system, they provide sound perception.
Now consider the parts of the skull: the brain and facial. In the process of anthropogenesis there was an increase in the size of the first of them. This is due to the development of the brain. With the evolution of man began to create an artificial environment. He built himself a house, grew plants, stocked up food. A powerful jaw at the same time lost its importance. Therefore, the size of the facial skull has significantly decreased. These differences are especially noticeable when comparing a skilled and intelligent person.
At first glance, it may seem that the skeleton of the head is formed by one large bone. In fact, its structure is like a mosaic. Some bones have their exact copy. They are paired, a total of eight. The remaining seven are unpaired. Each of them has its own name, in most cases associated with the location. So, the frontal is an unpaired skull bone. But the temporal and zygomatic have their own analogues.
The skeleton of the facial section
The composition of this part of the skull includes 15 bones. The largest of them are the zygomatic and maxillary. We list not the paired bones of the skull of this department:
- opener
- sublingual;
- lower jaw.
The paired bones of the facial section include:
- upper jaw;
- zygomatic;
- nasal;
- tearful;
- palatine;
- lower nasal concha.
The seam
Skeleton bones have different types of joints. They depend on the functions performed. For example, the bones of the limbs form joints - mobile joints. Elbow, knee, ankle, etc. They make possible the movement of individual parts and the whole body in space. The vertebrae are connected semi-mobile. Between them are cartilaginous plates. This structure provides elasticity and cushioning.
But the bones of the skull are connected motionless. Thanks to this, the brain is reliably protected from mechanical damage. This type of joint is called a seam. It is also characteristic of the pelvic bones.
Seams in children have an elastic structure. With age, they ossify and become more durable. Depending on the pattern, which is formed along the connection of the bones, there are flat, scaly and serrated seams.
An exception
All bones of the brain skull, as well as the facial, are connected motionless, except for the lower jaw. It is an unpaired skull bone. Despite the fact that there is a upper jaw, we were not mistaken. How is this possible. The upper jaw consists of two identical bones connected by a suture. Thus, she is paired on her own.
The lower jaw is mounted movably - with the help of a joint. This is very important for human life. Thanks to the movements of the lower jaw, a person is able to chew food and make sounds. These functions are associated with a decrease in the size of this bone during evolution. After all, its massiveness would greatly complicate the mastication and speed of pronunciation. In addition, the person began to eat chopped and thermally processed food. So the lower jaw has acquired optimal dimensions.
What are fontanelles
During the course of a person’s life, the skeleton of the head undergoes significant changes. Its weight in the process of growth of the body increases from 300 to 1400 g. In addition, the infant has a much larger brain area than the facial. The jaws are still underdeveloped during this period. Between the bones of the occipital region are areas consisting of cartilage. This is the fontanel. These sites have important biological significance. They provide a narrowing of the cranial vault during the movement of the fetus along the narrow genital tract.
In places of fontanelles, the baby's brain is protected only by soft connective tissues. Therefore, any impact or deformation can be deadly. There are two of them. Large is located between the frontal, which is the unpaired bone of the skull, and the parietal. The dimensions of this fontanel reach 2 cm in diameter. In colloquial speech, its location is called the "crown".
The small fontanel is located on the back of the head. In children who were born on time, it is already closed. Otherwise, it grows to a maximum of three months. A large fontanel will grow over about a year old child. The intensity of this process depends on the degree of development of the fetus and its availability of calcium.
Another meaning of fontanelles is heat regulation. Children's diseases are often accompanied by a significant increase in body temperature. This is very dangerous, since at high values it can lead to protein coagulation. In the fontanelles, brain tissue cools naturally.
Skull: brain
This part of the skeleton of the head is more massive. Here, the unpaired skull bone is:
- occipital;
- frontal;
- trellised;
- wedge-shaped.
To the paired are the parietal and temporal. In the brain, the base and the arch are distinguished.
Despite the general plan of the structure, the skull of men and women has its own distinctive features. So, in the former, the superciliary arches and paranasal sinuses are more pronounced, larger than the orbit. And the bones of the skull themselves in the male half of humanity have a large thickness. Women have less skull capacity. But this is not due to mental abilities, but to the general size of organisms.