The circulatory system is an important part of our body. Without it, the vital activity of human organs and tissues is impossible. Blood nourishes our body with oxygen and is involved in all metabolic reactions. Vessels and veins, through which the "energy fuel" is transported, play an important role, so even a small capillary must work at full capacity.
Only the heart matters
In order to understand the vascular system of the heart, you need to know a little about its structure. The four-chamber human heart is divided by a septum into 2 halves: left and 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 (superior and inferior vena cava) flow into the right atrium, and two pulmonary vessels into the left.
The circulatory system in the heart is also represented by the aorta and the pulmonary trunk. Through the aorta, which departs from the left ventricle, blood enters all organs and tissues of the human body, except for the lungs. From the right ventricle to the pulmonaryarteries, blood moves through the pulmonary circulation that feeds the bronchi and alveoli of the lung. This is how blood circulates in our body.
Venous apparatus of the heart: superior vena cava
Since the heart is small in volume, the vascular apparatus is also represented by medium-sized, but thick-walled veins. In the anterior mediastinum of the heart is a vein formed by the fusion of the left and right brachiocephalic veins. It is called the superior vena cava and belongs to the systemic circulation. Its diameter reaches 25 mm, and its length is from 5 to 7.5 cm.
The superior vena cava is located deep enough in the pericardial cavity. To the left of the vessel is the ascending aorta, and to the right is the mediastinal pleura. Behind it, the anterior surface of the root of the right lung protrudes. The thymus gland and the right lung are located in front. Such a fairly close relationship is fraught with compression and, accordingly, a deterioration in blood circulation.
The superior vena cava enters 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 human circulatory system.
What vessels represent the superior vena cava system?
The blood-carrying veins are located near the heart, so when the heart chambers relax, they seem to stick to it. Due to these peculiar movements, a strong negative pressure is created in the system.
Vessels included in the system of the superior vena cava:
- several veins extending from the walls of the abdomen;
- vessels that feed the neck and chest;
- veins of the shoulder girdle and arms;
- veins of the head and neck area.
Mergers and Confluences
What are the tributaries of the superior vena cava? The main tributaries can be called the brachiocephalic veins (right and left), which are formed as a result of the confluence of the internal jugular and subclavian veins and do not have valves. Due to the constant low pressure in them, there is a risk of air entering when injured. The left brachiocephalic vein runs behind the manubrium of the sternum and thymus, and behind it is the brachiocephalic trunk and the left carotid artery. The right blood thread of the same name starts its way from the sternoclavicular joint and is adjacent to the upper edge of the right pleura.
Also, an inflow is an unpaired vein, which is equipped with valves located at 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, an additional left superior vena cava occurs. In such cases, it can be considered an incapacitated inflow, which does not bear a load on hemodynamics.
Vessels of the head and neck in the system
The internal jugular vein is a fairly large vein that is part of the superior vena cava. Exactlyit collects blood from the veins of the head and part of the neck. It begins near the jugular foramen of the skull and, going down, forms a neurovascular bundle with the vagus nerve and the common carotid artery.
Jugular vein tributaries are divided into intracranial and extracranial. Intracranial include:
- meningeal veins;
- diploic veins (feeding the bones of the skull);
- vessels that carry blood to the eyes;
- veins of the labyrinth (inner ear);
- brain veins.
The diploic veins include: temporal (posterior and anterior), frontal, occipital. All of these veins carry blood to the sinuses of the dura mater and do not have valves.
Extracranial tributaries are:
- facial vein that carries blood from the labial folds, cheeks, earlobes;
- mandibular vein.
The pharyngeal veins, the superior thyroid veins and the lingual vein drain into the internal jugular vein in the middle third of the neck on the right.
Venas of the upper limbs included in the system
On the arm, the veins are divided into deep, lying in the muscles, and superficial, passing almost immediately under the skin.
Blood flows from the fingertips into the dorsal veins of the hand, followed by the venous plexus formed by superficial vessels. The cephalic and basilar veins are subcutaneous vessels of the arm. The main vein originates from the palmar arch and venous plexus of the hand on the back. It runs along the forearm and forms the median vein of the elbow, whichused for intravenous injections.
The veins of the palmar arches are divided into two deep ulnar and radial vessels, which merge near the elbow joint and two brachial veins are obtained. Then the brachial vessels pass into the axillary. The subclavian vein continues the axillary and has no branches. It is connected to the fascia and periosteum of the first rib, due to which its lumen increases when the arm is raised. The blood supply of this vein is equipped with two valves.
Thoracic vessels
Intercostal veins lie in the intercostal spaces and collect blood from the chest cavity and part of the anterior abdominal wall. The tributaries of these vessels are the spinal and intervertebral veins. They are formed from the vertebral plexuses located inside the spinal canal.
The vertebral plexuses are multiple anastomosing vessels that extend from the foramen magnum to the top of the sacrum. In the upper part of the spinal column, small plexuses develop into larger ones and flow into the veins of the spine and neck.
Causes of compression of the superior vena cava
The causes of such an ailment as superior vena cava syndrome are pathological processes such as:
- oncological diseases (adenocarcinoma, lung cancer);
- Metastases from breast cancer;
- tuberculosis;
- retrosternal goiter of the thyroid gland;
- syphilis;
- soft tissue sarcoma and others.
Often pressure is due to germinationmalignant tumor in the wall of the vein or its metastasis. Thrombosis can also cause an increase in pressure in the lumen of the vessel up to 250-500 mm Hg, which is fraught with rupture of the vein and death of a person.
How does the syndrome manifest itself?
Symptoms of the syndrome can develop instantly without warning. This occurs when the superior vena cava becomes blocked by an atherosclerotic thrombus. In most cases, symptoms develop gradually. The patient appears:
- headache and dizziness;
- cough with increasing shortness of breath;
- chest pain;
- nausea and dysphagia;
- changing facial features;
- fainting;
- swollen veins in chest and neck;
- puffiness and puffiness of the face;
- cyanosis of the face or chest.
Several studies are required to diagnose the syndrome. Radiography and Doppler ultrasound have proven themselves well. With their help, it is possible to differentiate diagnoses and prescribe appropriate surgical treatment.
