The human skull is not only the most important bone formation, but also the most visually noticeable. Therefore, all his changes cannot go unnoticed. The stages of such transformations are quite relative and each person is individual, but there are general principles depending on age.
The human skull undergoes many changes throughout life. This primarily concerns its appearance. Conventionally, there are five large periods of such transformations. Let's consider each of them in more detail.
First period
This period is the most active stage of head growth and lasts for the first seven years of human life. From the moment of birth to six months, the volume of the cerebral region of the skull almost doubles. By the age of two, its volume triples, and by the age of five, it is three-quarters of the volume of the entire skull. This ratio persists throughout life. It is during this period that the cranial fossae deepen significantly, and the occipital part of the head begins to protrude. In addition, the membranous tissue of the cranial vault and cartilaginous tissue in the occipital bone are modified and gradually disappear. The first (initial stage) occursformation of sutures of the bone skeleton of the head. This period is extremely important, because the suture of the skull is intended not only to hold the bones of the head together, but, more importantly, is the place of their growth in width.
Classification of skull sutures
Seams are divided according to their shape into the following:
- toothed;
- scaly;
- flat.
The serrated suture of the skull is formed by two bony surfaces, when one has protrusions, and the other has notches that fill these protrusions. This type of seam is the most durable. When two edges of adjacent bones are superimposed, a scaly suture of the skull is formed. All seams are filled with connective tissue, which gives strength and mobility to such joints. And the third type of seams is flat. The flat suture of the skull is formed by the contact of slightly wavy or completely flat surfaces of the bones. With the help of this type of suture, the bones of the facial skull are connected to each other, and their name depends on the bone formations connecting to each other.
Second period of change
Over the next five years, the bones of the head grow much more slowly. There is a visually more noticeable change in the growth and shape of the facial part of the skull (eye sockets, nasal cavity and upper jaw). The fontanelles closed during the neonatal period completely disappear, and the sutures are filled with connective tissue.
Third period
This period coincides with human puberty and lasts for ten years (from14-15 years of age up to 25 years). There is a final growth of the skull and the entire axial skeleton. During this period of life (unlike the previous two), there is a more intensive growth of the facial skull, and not the brain. The suture of the skull, as an anatomical formation, becomes more durable, and the period of its ossification begins, which lasts until old age. The base of the skull is enlarged in all directions, not just in width. Furrows, protrusions, tubercles and air sinuses are finally formed.
Fourth Period
From the age of 25 to 45 there are no changes in the development of the bones of the head. During this period, the suture of the skull ossifies. In very rare cases, stitches can last a lifetime.
Fifth period
This stage lasts from the period of closure of sutures until old age. To a greater extent, not anatomical changes occur, but structural ones. The facial skull visually changes due to loss of teeth and atrophy of the alveolar processes. With age, the thickness of the spongy substance and the compact plate decreases, and the skull becomes lighter. Due to bone resorption and changes in its mineral composition, bones become more brittle, crack and break.
Conclusion
The human skull is the so-called head skeleton. This anatomical structure is extremely important not only for protecting the brain and sensory organs. It shapes our appearance (face).
The suture of the skull, being a structural and functional unit, playsan important role in connecting the bones of the skull to each other. In children, the sutures are more elastic, and with age they ossify.
Staging of the development of the bones of the skull has an age framework. So, the neonatal period, when fontanelles are still preserved (webbed stage), with the maturation of a person, it passes into the cartilaginous stage, and then into the bone one.
By the time of birth, the formation of the skull itself is not completed. There are five stages of its development. So, from the moment of birth to school age (6-7 years), the skull grows mainly in height, the next five to seven years are a period of relative rest, and with the onset of puberty and up to the age of 25, modifications occur mainly in its facial part.
