The circulatory system is an important component 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. The vessels and veins used to transport “energy fuel” play an important role, so even a small capillary should work at full strength.
Only heart is more important
In order to understand the vascular system of the heart, you need to know a little of its structure. The four-chamber human heart is divided by a partition into 2 halves: left and right. Each half has an atrium and a ventricle. They are also separated by a septum, but with valves allowing 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 pulmonary trunk. According to the aorta extending from the left ventricle, blood enters all organs and tissues of the human body, except the lungs. From the right ventricle through the pulmonary artery, blood moves along the small circle of blood 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. A vein is located in the anterior mediastinum of the heart, formed by the fusion of the left and right brachiocephalic veins. It is called the superior vena cava and belongs to a large circle of blood circulation. Its diameter reaches 25 mm, and the 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 her stands the front surface of the root of the right lung. The thymus gland and the right lung are located in front. Such a fairly close relationship is fraught with compression and, accordingly, poor circulation.
The superior vena cava 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 human circulatory system.
What vessels is represented by the superior vena cava system?
Blood-carrying veins are located near the heart, so when the heart chambers are relaxed, they seem to stick to it. Due to these peculiar movements, a strong negative pressure is created in the system.
Vessels entering the superior vena cava system:
- 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.
Mergers and acquisitions
What are the inflows of the superior vena cava? The main tributaries can be called the brachiocephalic veins (right and left), resulting from the fusion of the internal jugular and subclavian veins and without valves. Due to the constant low pressure in them, there is a risk of air ingress during injury. The left brachiocephalic vein passes behind the hilt of the sternum and thymus, and behind it is the brachiocephalic trunk and left carotid artery. The right blood thread of the same name begins its path 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 the esophagus to the point of confluence with the superior vena cava. She collects blood from the intercostal veins and chest organs. An unpaired vein lies on the right on the transverse processes of the thoracic vertebrae.
With abnormalities of the heart, an additional left superior vena cava occurs. In such cases, it can be considered a disabled inflow, which does not bear the load on hemodynamics.
Vessels of the head and neck in the system
The internal jugular vein is a rather large vein that is part of the superior vena cava system. It is she who collects blood from the veins of the head and partially the neck. It begins near the jugular opening of the skull and, going down, forms a neurovascular bundle with the vagus nerve and the common carotid artery .
The inflows of the jugular vein are divided into intracranial and extracranial. Intracranial include:
- meningeal veins;
- diploic veins (nourishing bones of the skull);
- blood vessels carrying blood to the eyes;
- labyrinth veins (inner ear);
- veins of the brain.
The diploic veins include: temporal (anterior and posterior), frontal, occipital. All these veins carry blood to the sinuses of the dura mater and have no valves.
Extracranial tributaries are:
- facial vein carrying blood from the labial folds, cheeks, earlobes;
- the mandibular vein.
Pharyngeal veins, superior thyroid veins and lingual veins flow into the internal jugular vein on the middle third of the neck on the right.
Veins of the upper extremities 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 to the back veins of the hand, followed by the venous plexus formed by the superficial vessels. The head and main veins are the saphenous vessels of the arm. The main vein originates from the palmar arch and venous plexus of the hand on the back side. It passes along the forearm and forms the median vein of the elbow, which is used for intravenous injection.
The veins of the palmar arches are divided into two deep ulnar and radial vessels, which merge near the elbow joint and two shoulder veins are obtained. Then the humeral vessels pass into the axillary. The subclavian vein continues axillary and has no branches. It is connected to the fascia and periosteum of the first rib, due to which its clearance increases when raising the arm. The blood supply to this vein is equipped with two valves.
Chest vessels
Intercostal veins run in the intercostal spaces and collect blood from the chest cavity and partially the anterior abdominal wall. The inflows of these vessels are the spinal and intervertebral veins. They are formed from the vertebral plexuses located inside the spinal canal.
Vertebral plexuses are vessels repeatedly anastomosing between themselves, extending from the occipital foramen to the upper part of the sacrum. In the upper part of the spinal column, small plexuses grow into larger ones and flow into the veins of the spine and occiput.
Causes of compression of the superior vena cava
The causes of such an ailment as the superior vena cava syndrome are pathological processes such as:
- oncological diseases (adenocarcinoma, lung cancer);
- breast cancer metastases;
- tuberculosis;
- retrosternal goiter of the thyroid gland;
- syphilis;
- soft tissue sarcoma and others.
Often, compression occurs due to the growth of a malignant tumor into the wall of the vein or its metastasis. Thrombosis can also cause an increase in pressure in the lumen of the vessel to 250-500 mm Hg, which is fraught with rupture of a vein and death of a person.
How is the syndrome manifested?
Symptoms of the syndrome can develop instantly without precursors. This occurs when the superior vena cava is blocked by an atherosclerotic thrombus. In most cases, symptoms increase gradually. The patient appears:
- headache and dizziness;
- cough with increasing shortness of breath;
- chest pain;
- nausea and dysphagia;
- change in facial features;
- fainting
- swelling of veins on the chest and neck;
- puffiness and puffiness of the face;
- cyanosis of the face or chest.
To diagnose the syndrome, several studies are required. Radiography and Doppler ultrasound have proven themselves well. With their help, it is possible to differentiate diagnoses and prescribe appropriate surgical treatment.