Areas of the head. Human head anatomy

In this article, you can find out what areas of the head are, how this part of the body is structured, and why did it even appear during evolution? The article begins with the simplest - basic information about the organization.

What is meant by the skeleton of the head or, more simply, the skull? This is a collection of multiple bones, paired or not, spongy or mixed. The skull contains only two large departments:

• cerebral (cavity in which the brain is located);
• facial (it is here that some systems, such as the respiratory or digestive, originate; in addition, here you can find more sensory organs).

As for the brain, it is worth mentioning that this area is also divided into two:

• cranial vault;
• its foundation.

Evolution

It is important to know that far from always vertebrates had such a large head. Let's look a little into the past. This part of the body appeared in ancient vertebrates during the fusion of the first three segments of the spine. Prior to this phenomenon, the same segmentation was observed. Each vertebra had its own pair of nerves. The nerves of the first vertebra were responsible for the sense of smell, the second for vision, the third for hearing. Over time, the load on these nerves grew, more and more information was required to be processed, which led to a thickening of these segments responsible for these sensory organs. So they merged into the brain, and the union of the vertebrae formed a brain capsule (like a skull). Note that even the head of a modern person is still divided into the segments from which it was formed.

What are the average head sizes of an adult? Length - 17-22 cm, width - 14-16 cm, height - 12-16 cm, circumference - 54-60 cm. The length of the head is usually more than the width, so it is not round, but ellipsoidal. It is very interesting that the numbers (length, width and height) are not constant, they either increase or decrease. And it all depends on the location of the person.

Brain

Before moving on to studying the areas of the head, it is worth saying that the head is not just considered the most important part of the body. After all, it is located here:

• brain;
• organs of vision;
• hearing organs;
• organs of smell;
• organs of taste;
• nasopharynx;
• tongue;
• chewing apparatus.

Now we learn a little more about the brain. What is it and how is it arranged? This organ is formed from nerve fibers. Neurons (these are brain cells) are able to control the work of the whole human body by generating an electrical impulse. In total, twelve pairs of nerves that control the functioning of organs can be observed. The signals supplied by the brain reach their destination through the spinal cord.

The brain is always in the fluid, which prevents it from contacting the cranium during head movement. In general, our brain has pretty good protection:

• hard connective tissue;
• soft connective tissue;
• choroid
• cerebrospinal fluid.

The fluid in which our brain “floats” is called cerebrospinal fluid. The pressure of this fluid on the organ is considered to be intracranial pressure.

It is also important that the work of the brain and organs located on the head requires high energy costs. For this reason, we can observe intense blood circulation in this area. It:

1. Nutrition: carotid and vertebral arteries.
2. Outflow: internal and external jugular veins.

So at rest, the head consumes about fifteen percent of the total blood volume of the body.

Skull and muscle

The skeleton of the head (skull) has an equally complex structure. Its main function is to protect the brain from mechanical damage and other external influences.

The entire human skull is formed by 23 bones. They are all motionless except for one - the lower jaw. As mentioned earlier, two departments can be distinguished here:

• cerebral;
• facial.

Bones related to the facial section (total 15), can be:

• paired - upper jaw, palatine bone, lacrimal, lower nasal concha;
• unpaired - lower jaw, opener, hyoid.

Paired bones of the brain:

• parietal;
• temporal lobe.

Unpaired:

• occipital;
• frontal;
• wedge-shaped;
• trellised.

The entire brain section consists of eight bones in total.

The cervical region, to which the cranium is attached, allows the head to move. The movement is provided by the muscles of the neck. But on the head itself there are also muscle fibers that are responsible for facial expressions, one exception is the masticatory muscles, which are considered the strongest in this area.

Head area

The whole head is conditionally divided into 13 areas. There are also paired and unpaired. And so, six of them are referred to unpaired regions.

1. Frontal region of the head (attention is focused on it in the next section of the article).
2. Parietal (detailed information will be presented to your attention later).
3. Occipital (discussed in more detail in a separate section of the article).
4. Nasal, which is fully consistent with the contour of our nose.
5. Oral, also corresponds to the contour of the mouth.
6. The chin, which is separated from the oral with the help of the chin labial groove.

Now move on to listing seven paired areas. This includes:

1. The buccal region, separated from the nose and mouth by the nasolabial sulcus.
2. Parotid chewing (contours of the parotid gland and muscles responsible for the chewing reflex).
3. Temporal region of the head (contours of the scales of the temporal bone, located below the parietal region).
4. Orbital (contour of the orbits).
5. The infraorbital (below the orbits).
6. Zygomatic (contour of the cheekbones).
7. Mastoid (this bone can be found behind the auricle, which, as it were, covers it).

Frontal region

Now we turn to a detailed examination of the frontal region of the head. The boundaries of the anterior section are the nasolabial suture, the infraorbital edges, the posterior is the parietal region, the sides are the temporal region. This department captures even the scalp.

As for blood supply, it is carried out due to the following arteries:

• subblock;
• infraorbital.

They depart from the ophthalmic artery, which is a branch of the carotid. A well-developed venous network is observed in this area. All vessels of this network form the following veins:

• subblock;
• infraorbital.

The latter, in turn, partially merge into the angular, and then into the facial veins. And the other part goes into the eye.

Now briefly about innervation in the frontal region. These nerves are branches of the eye and have the names:

• subblock;
• infraorbital.

As it is not difficult to guess, they pass with the vessels of the same name together. The motor nerves are branches of the facial nerve, called the temporal.

Parietal region

This area is limited by the contours of the bones of the crown. You can imagine it if you draw the projection lines:

• before - a coronal seam;
• back - lambdoid seam;
• Boca - temporal lines.

Arterial vessels, which are processes of the parietal branches of the temporal artery, contribute to blood supply. Outflow is the parietal branch of the temporal vein.

Innervation:

• before - the final branches of the infraorbital nerve and frontal;
• boca - ear-papillary nerve;
• butt - occipital nerve.

Occipital region

The occipital region of the head is below the parietal, and is limited to the posterior region of the neck. So the boundaries are:

• top and sides - cinch stitch;
• the bottom is the line between the apices of the mastoid processes.

Arteries contribute to blood supply:

• occipital;
• back ear.

The outflow is the occipital, and then the vertebral vein.

The innervation is carried out by the following types of nerves:

• suboccipital (motor);
• large occipital (sensitive);
• small occipital (sensitive).

Nervous system

The article briefly describes the nervous system of some areas of the human head. From the table you will find out more detailed information. In total, the head contains 12 pairs of nerves that are responsible for sensations, secretion of tears and saliva, innervation of the muscles of the head, and so on.

Circulatory system

Studying the anatomy of the head, one cannot ignore such a complex but very important topic as the circulatory system. It provides the blood circulation of the head, so that a person can live (eat, breathe, drink, socialize, and so on).

For the work of our head, or rather for the brain, a lot of energy is needed, which requires a constant flow of blood. It has already been said that even at rest, our brain consumes fifteen percent of the total blood volume and twenty-five percent of the oxygen that we receive when breathing.

What arteries feed our brain? Mainly:

• vertebrates;
• sleepy.

Outflow from the bones of the cranium, muscles, brain and so on should also occur. This is due to the presence of veins:

• internal jugular;
• external jugular.

Arteries

As already mentioned, the vertebral and carotid arteries, which are presented in the form of pairs, are involved in the nutrition of the human head. The carotid artery is the basis of this process. It is divided into 2 branches:

• outer (enriches the outer part of the head);
• internal (passes into the cavity of the skull itself and branches, providing blood flow to the eyes and other parts of the brain).

The blood flow to the muscles is carried out by the external and internal carotid artery. About 30% of the brain’s nutrition is provided by the vertebral arteries. Basilar provides work:

• cranial nerves;
• inner ear;
• medulla oblongata;
• cervical spinal cord;
• cerebellum.

Blood supply to the brain varies depending on the condition of the person. Mental or psychophysiological overloads increase this indicator by 50%.

Veins

Considering the anatomy of the human head, it is difficult to go past a very important topic - the venous structure of this part of the body. To begin with, what are venous sinuses. These are large veins that collect blood from the following parts:

• skull bones;
• muscles of the head;
• meninges;
• brain;
• eyeballs;
• inner ear.

You can also meet their other name, namely - venous collectors, which are located between the sheets of the brain membrane. Leaving the cranium, they pass into the jugular vein, which runs near the carotid artery. You can also distinguish the external jugular vein, which is slightly smaller and located in the subcutaneous tissue. It is here that blood is collected from:

• eye;
• a nose;
• the mouth;
• chin.

Generally speaking, everything that is listed above is called superficial formations of the head and face.

Muscle

To speak very briefly, then all the muscles of our head can be divided into several groups:

• chewing;
• mimic;
• cranial vault;
• sensory organs;
• upper digestive system.

The functions performed can be guessed by their names. For example, chewing makes it possible to chew food, but facial expressions are responsible for facial expressions of a person and so on.

It is very important to know that absolutely all muscles, regardless of their main purpose, participate in speech.

Skull

The entire skull formed by the bones of the head is divided into two sections:

• facial;
• cerebral.

The first is located between the orbits and the chin, and forms the initial sections of some body systems (more specifically, the digestive and respiratory). In addition, the facial section is the place of attachment of certain muscle groups:

• chewing;
• mimic.

What is located in this department:

• eye sockets;
• nasal cavity;
• oral cavity;
• tympanic cavity.

Particular attention should be paid to the zygomatic bone, which is the place of attachment of the bulk of the muscles of the face. It is located below the orbit and performs an important function - protecting the eyes and nose from mechanical damage.

It is important to note the jaw, represented by the upper paired bone and lower unpaired. The lower jaw is the only mobile bone to which strong masticatory muscles are attached.

Let's pay attention to the intermaxillary region, which is also called the deep section of the face. Limitations:

• the outer part is a branch of the lower jaw;
• the inner part is the tubercle of the upper jaw;
• upper - lower surface of the large wing of the sphenoid bone.

Briefly about the brain, which is designed to protect the brain and other structures that are associated with it. A department of 8 bones is formed, the main ones are:

• occipital;
• parietal;
• frontal;
• temporal lobe.

It is important to note that the cranium is not continuous, it has sinuses and openings that allow nerves and blood vessels to enter the brain. At the base of the skull of a human head is an occipital foramen connecting the cranial cavity and the spinal canal.