The circulatory system is an important part of our body. Without it, the vital activity of human organs and tissues is impossible. Blood feeds our body with oxygen and participates in all metabolic reactions. Vessels and veins, through which the "energy fuel" is transported, play an important role, so even a small capillary should work at full force.
Only the heart is more important
In order to understand the vascular system of the heart, you need to know a little its structure. The four-chambered human heart is divided by a partition into two halves: the left and the right. Each half has an atrium and a ventricle. They are also separated by a septum, but with valves that allow the heart to pump blood. The venous apparatus of the heart is represented by four veins: two vessels (upper and lower hollow veins) flow into the right atrium, and into the left atrium - two pulmonary veins.
The circulatory system in the heart is represented by aorta and pulmonary trunk. On the aorta that extends from the left ventricle, the blood enters all organs and tissues of the human body, except the lungs. From the right ventricle through the pulmonary artery, blood moves along a small circle of blood circulation, which feeds the bronchi and lung alveoli. That's how blood circulates in our body.
Venous apparatus of the heart: the superior hollow vein
Since the heart is small in volume, the vascular apparatus is also represented by small, but thick-walled veins. In the anterior mediastinum of the heart there is a vein formed by the fusion of the left and right brachiocephalic veins. It is called the upper vena cava and refers to a large range of blood circulation. Its diameter reaches 25 mm, and the length is from 5 to 7.5 cm.
The superior hollow vein is located deep enough in the pericardial cavity. To the left of the vessel is the ascending part of the aorta, and to the right is the mediastinal pleura. Behind it protrudes the anterior surface of the root of the right lung. The thymus gland and the right lung are located in the front. Such a fairly close relationship is fraught with compression and, consequently, deterioration of blood circulation.
The superior hollow vein flows into the right atrium at the level of the second rib and collects blood from the head, neck, upper chest and arms. There is no doubt that this small vessel is of great importance in the circulatory system of man.
What are the vessels of the upper vena cava system?
Blood carrying veins are near the heart, so when the heart cells relax, they seem to suck it. Due to these peculiar movements, a strong negative pressure is created in the system.
Vessels entering the system of the superior vena cava:
- A few veins running away from the walls of the abdomen;
- Vessels that nourish the neck and thorax;
- Veins of the shoulder girdle and arms;
- Veins of the head and neck area.
Mergers and confluences
What are the inflows of the superior vena cava? The main tributaries can be called brachiocephalic veins (right and left), resulting from the fusion of the internal jugular and subclavian veins and not having valves. Because of the constant low pressure in them, there is a risk of air ingress during injury. The left brachiocephalic vein passes behind the grip part of the sternum and thymus, and behind it is the brachiocephalic trunk and the left carotid artery. The right-named blood-line thread begins its path from the sternoclavicular joint and fits to the upper edge of the right pleura.
Also, the influx is the unpaired vein, which is equipped with valves located in its mouth. This vein originates in the abdominal cavity, then passes along the right side of the vertebral bodies and through the diaphragm, following behind the esophagus to the point of confluence with the superior vena cava. It collects blood from the intercostal veins and chest organs. The unpaired vein lies on the right on the transverse processes of the thoracic vertebrae.
With anomalies of the heart, there is an additional left upper vena cava. In such cases, it can be considered an invalid tributary, which does not carry a burden on hemodynamics.
Head and neck vessels in the system
The internal jugular vein is a fairly large vein entering the system of the superior vena cava. It is she who collects blood from the veins of the head and partly the neck. It begins near the jugular aperture of the skull and, going down, forms a vascular-neural bundle with a vagus nerve and a common carotid artery .
Inflows of the jugular vein are divided into intracranial and extracranial. Intracranial include:
- Meningeal veins;
- Diploic veins (nourishing the skull bones);
- Vessels carrying blood to the eyes;
- Veins of the labyrinth (inner ear);
- Veins of the brain.
Diplic veins include: temporal (posterior and anterior), frontal, occipital. All these veins carry blood in the sinuses of the hard shell of the brain and do not have valves.
Extracranial tributaries are:
- The facial vein carrying blood from the labial folds, cheeks, earlobes;
- Dormant jaw.
Pharyngeal veins, the upper thyroid veins and lingual, flow into the internal jugular vein on the middle third of the neck to the right.
The veins of the upper limbs that make up the system
On the arm veins are divided into deep, lying in the muscles, and superficial, passing almost immediately under the skin.
Blood comes from the fingertips into the dorsal veins of the hand, followed by the venous plexus formed by the surface vessels. The head and main veins are the subcutaneous vessels of the arm. The main vein originates from the palmar arch and venous plexus of the brush on the back side. It passes over the forearm and forms the medial vein of the elbow, which is used for intravenous injections.
The veins of the palmar arcs are divided into two deep ulnar and radial vessels that merge near the elbow joint and produce two brachial veins. Then the humeral vessels pass into the axillary spaces. The subclavian vein extends axillary and does not have branches. It is connected to the fascia and periosteum of the first rib, thereby increasing its lumen when the arm is raised. The blood supply of this vein is equipped with two valves.
Vessels of the chest
Intercostal veins run through the intercostal spaces and collect blood from the thoracic cavity and partly the anterior abdominal wall. Inflows of these vessels are the dorsal and intervertebral veins. They are formed from vertebral plexuses located inside the spinal canal.
Vertebral plexuses are repeatedly anastomosing the vessels between them, extending from the occipital opening to the upper part of the sacrum. In the upper part of the spinal column small plexuses grow into larger plexuses and flow into the veins of the spine and occiput.
Causes of compression of the superior vena cava
The causes of such a disease as the syndrome of the inferior vena cava are such pathological processes as:
- Oncological diseases (adenocarcinoma, lung cancer);
- Metastases in breast cancer;
- Zagrudinny goiter of the thyroid gland;
- Soft tissue sarcoma and others.
How does the syndrome manifest?
The symptomatology of the syndrome can develop instantly without precursors. This occurs when the upper vena cava is blocked by an atherosclerotic thrombus. In most cases, the symptoms grow gradually. The patient appears:
- Headache and dizziness;
- Cough with increasing dyspnea;
- Pain in the chest;
- Nausea and dysphagia;
- Change of facial features;
- Swelling of the veins on the chest and neck;
- Puffiness and puffiness of the face;
- Cyanosis of the face or chest.
Several studies are needed to diagnose the syndrome. X-rays and Doppler ultrasound have proved to be very useful. With their help, it is possible to differentiate diagnoses and prescribe appropriate surgical treatment.