Subclavian artery and its pathologies. The structure of the right and left subclavian arteries The continuation of the subclavian artery is

The subclavian artery is one of the main human arteries, supplying the head, upper limbs and upper torso of a person. The subclavian artery is paired, that is, there are right and left subclavian arteries. For prevention, drink Transfer Factor. They begin in the anterior mediastinum. The right one originates from the brachiocephalic trunk, and the left one - directly from the aortic arch. Therefore, the left subclavian artery is longer than the right by approximately 4 cm.
The artery forms an upwardly convex arc that goes around the dome of the pleura. Then through the upper aperture of the chest it goes to the neck, leads into the interscalene space, where it lies in the groove of the same name of the first rib and below the lateral edge of this rib passes into the axillary cavity and continues like the axillary artery.
The walls of the subclavian artery consist of three membranes: internal, middle and external. The inner membrane is formed from the endothelium and the pidendothelial layer. The middle shell consists of smooth muscle cells and elastic fibers, the ratio of which to each other is approximately the same. The outer shell is formed by loose fibrous connective tissue, which contains bundles of smooth myocytes, elastic and collagen fibers. It contains vascular vessels that provide trophic function.
In the subclavian artery, three sections are topographically distinguished: the first - from the point of origin to the interscalene space, the second - in the interscalene space, and the third - from the interscalene space to the upper opening of the axillary cavity. In the first section, three branches depart from the artery: the vertebral and internal mammary arteries, the thyrocervical trunk, in the second section - the costocervical trunk, and in the third - sometimes the transverse artery of the neck.
The vertebral artery, whose normal lumen is 1.9 mm–4.4 mm, is considered a branch of the subclavian artery. The vertebral artery is the most significant of the branches of the subclavian artery. It starts from its upper surface, flows into the transverse foramen of the sixth cervical vertebra and lies in the canal, which arose due to the holes in the transverse processes of the cervical vertebrae. The vertebral vein also runs along with the artery. The vertebral artery emerges from the transverse foramen of the first cervical vertebra and runs in its groove. Having passed the posterior atlanto-occipital membrane and the dura mater, the artery then lies through the foramen magnum and the posterior cranial fossa. This is where its intracranial part begins. Behind the pons of the brain, this artery connects with a similar artery on the opposite side, forming the basilar artery, which is unpaired. Continuing its path, the basilar artery is adjacent to the basilar groove and the lower surface of the bridge at its anterior edge.
In the cranial cavity, the following branches depart from the vertebral artery: the anterior spinal artery - right and left, the paired posterior spinal artery and the posterior inferior cerebellar artery, which branches on the lower surface of the cerebellar hemisphere.

The human circulatory system is a complex pattern of intricate veins, arteries and many capillaries. The subclavian artery is a paired and very large vessel; it belongs to the arteries of the great circle. It receives blood from the aortic arch and brachiocephalic trunk and supplies the occipital region, part of the spinal cord located in the cervical region, and the cerebellum with nutrients. Also, blood from this vessel supplies oxygen to the upper limbs, shoulder girdle and some parts of the peritoneum and chest.

Anatomy

This artery is a convex arch-shaped vessel located in the anterior mediastinum. Heading up the chest laterally, the vessel bends around the pleura and overlaps the upper part of the lung. The topography of the subclavian artery, relative to the neck area, contributes to the supply of oxygen to the neck muscles and the back of the head.

The vessel is located on the surface and is visible next to the brachial plexus of nerves. The anatomy of the subclavian artery makes it possible to use it for administering medications, and also, in case of heavy bleeding, there is an excellent chance to prevent unpleasant consequences.

Departing from the brachial plexus, the vessel bends over the rib. Here a groove of the subclavian artery is formed, which extends under the collarbone and rises into the armpit. In this area, the vessel passes into the axillary artery. After passing through the armpit, the artery enters the shoulder and becomes the brachial artery. In the area of the elbow joint, the subclavian artery diverges into the ulnar and radial arteries.

Main branches

The left subclavian artery, like the right one, is very large and is part of the systemic circulation. On its way through the body, it gives off several branches through which blood passes to supply oxygen and nutrients to the internal organs, skin, and various parts of the body.

At certain points this vessel diverges into five branches.

Internal thoracic artery

This vessel departs from the main artery in the area of the pleural dome. It passes between the intrathoracic fascia and the pleura, heading towards the lower part of the sternum.

In turn, the thoracic internal artery is divided into:

Mediastinal branch;
Tracheal;
Perforating;
Thymus;
Bronchial;
Anterior intercostal;
Pericardiodiaphragmatic;
Superior epigastric;
Muscular-diaphragmatic.

Vertebral artery

This vessel originates several millimeters medial to the anterior edge of the scalene muscle, in the interscalene space. The anterior part of the artery is covered by the inferior supraclavicular thyroid vessel and the carotid artery.

This branch from the subclavian artery is one of the largest and gives off the following branches:

Posterior inferior cerebellar;
Villous;
Posterior, anterior spinal;
Meningeal.

Thyroid trunk

This vessel has a length of about 0.5-1.5 cm. It branches from the subclavian artery in the area of the anterior scalene muscle.

Just like other branches, it is divided into several arteries branching from it:

Ascending cervical;
Superficial cervical;
Inferior thyroid;
Suprascapular.

Costocervical trunk

This large vessel extends from the wall of the subclavian artery to the small axillary vessel in the interscalene space and is located at the first rib, at its head.

The trunk along its course is divided into the following branches of the great subclavian artery:

Cervical transverse;
Intercostal overhang;
Cervical deep;
Superficial.

Basilar artery

This vessel is formed as a result of the connection of two vertebral arteries in the area of the posterior edge of the bridge.

The following branches of blood channels depart from it:

Posterior brain;
Artery of the labyrinth;
Superior cerebellar;
Pontine artery;
Inferior anterior cerebellar;
Midbrain.

Departments and functions

The surface location of this vessel is very convenient for puncture. Subclavian artery catheterization is also often performed in this area of the neck. Experts give preference to this area because it is accessible, due to its anatomical features, the artery has a more than suitable lumen diameter and a stable position.

During catheterization, the placed catheter will not come into contact with the walls of the vessel, and the drug that will be administered through it will quickly reach its target, actively influencing hemodynamics.

The main sections of the subclavian artery are three sections:

Interstitial space. The vertebral and paired arteries depart from it;
Costocervical trunk;
Branching of the transverse cervical artery.

The subclavian vessel, located in the 1st section, passes into the skull. Its function is to supply blood to the brain and neck muscles. The internal mammary artery supplies blood to the thyroid gland, diaphragm and bronchi. It is divided into the overhanging intercostal vessel and other adjacent arteries.

Palpation

Palpation and examination of the subclavian artery (palpation) is carried out according to the pattern of palpation of the apical impulse, that is, with three or two fingers. First, the arteries at the edge of the sternocleidomastoid muscles above the collarbones are examined. Then a transition is made to the area of the depth of the subclavian fossae under the collarbones at the edges of its deltoid muscles. The examination is carried out very carefully, using the method of applying fingers and pressing on the soft tissue in the area of the externally examined area.

In a healthy person who is at rest, the subclavian arteries will not be palpated, or their pulsation will be subtle. This is explained by their sufficient depth. You can feel a strong pulsation in people with poor development of the muscle tissue of the shoulder and neck, after physical exertion, emotional shock, as well as in asthenic patients.

With pathology of the subclavian artery, its pulsation is clearly manifested. This phenomenon can be observed with aortic insufficiency and hyperkinetic type of hemodynamics. With a vascular aneurysm, pulsation is usually felt in the supraclavicular area, slightly limited (2-3 cm). The weakening of the pulsation of these arteries can be accurately assessed by palpating them simultaneously using both hands. This may be due to a violation of their patency (thrombosis, compression, atheromatosis) or if there is an anomaly - an aberrant right subclavian artery.

Possible pathologies

The most common disease that affects the subclavian artery and its branches is stenosis. This pathology develops due to the presence of atherosclerosis or thrombosis. The disease can be either congenital or acquired. People who smoke, are overweight and suffer from diabetes are at risk of getting stenosis.

Also, quite often, stenosis develops against the background of impaired metabolism, due to neoplasms and a long-term inflammatory process. During the first course of the disease in acute form, a significant decrease in blood flow is possible, which can cause stroke or ischemia. With stenosis of the subclavian arteries, the majority of patients complain of severe pain, which intensifies with exercise.

Treatment method

A disease such as stenosis can be treated with medication, in its mild form, interventionally and surgically. But the main methods of therapy, according to experts, are bypass surgery and stenting. These treatments have been used for a very long time and have an excellent success rate during the procedure.

Bypass surgery

If stenosis is detected in the 2nd section of the artery, bypass surgery is indicated. If the ipsilateral common carotid artery is damaged, crossover bypass grafting is preferred. This method of surgical intervention does not injure the patient’s tissues and organs, does not require the use of general anesthesia, takes little time and does not cause serious postoperative complications. Before performing it, it is necessary to perform an ultrasound.

If the great subclavian artery is damaged on the left or on both sides, then its reconstruction in the affected area will first be necessary. If the operation is unsuccessful, repeated intervention is difficult. Contralateral lesions of the subclavian vessels require preliminary elimination of the style syndrome, only then can bypass surgery be started. Reconstruction of the damaged section of the artery is possible only with non-regressive vertebrobasilar insufficiency. All surgical interventions, be it bypass surgery, stenting and others, are not carried out without a complete preliminary examination of the patient and an accurate diagnosis.

Stenting

This method is indicated for patients who have a hypersthenic physique and a special topography of their subclavian arteries. The first section of the artery in such people is difficult to feel. The stenting method is very convenient and significantly prevails over surgical abdominal intervention. During this gentle process, no changes occur in the arteries, and body tissues are not injured.

Using stenting, doctors increase the lumen of the affected vessel. For this purpose, a catheter and a balloon-shaped stent are used. All procedures are performed under local anesthesia. The movement of the stent through the artery occurs under the supervision of an experienced specialist who regulates its location. Having reached the narrowing area, the device opens. If the stent is not open enough, angioplasty is performed. The total operation time is no more than 2 hours.

Complications

Although such operations cannot be called complex, they still have a fairly long rehabilitation period. After stenting, it is recommended to take painkillers, since the puncture sites and incisions of the soft tissues and arteries may hurt. Postoperative complications are extremely rare, since before the procedure the patient undergoes a complete examination of the entire body (ultrasound, etc.). But still, the body’s reaction under certain circumstances can be unpredictable (for example, if there is a defect - an aberrant subclavian artery).

After stenting, the patient may experience:

Allergy to drugs;
Increase in temperature;
Headache;
Wound infection;
Air embolism;
Stent migration;
Bleeding at puncture sites;
Arterial thrombosis;
Neurological complications.

Interventional therapy of stenosis and other diseases of the subclavian arteries using stenting and agioplasty is a modern minimally invasive measure. Such effective procedures are carried out in a very short time and do not require long-term hospitalization. It is enough to first undergo an ultrasound and pass the necessary tests.

Question:

I beg you to answer this question. I did an ultrasound scan, diagnosis: atherosclerosis of the right subclavian artery (the intima-media complex is thickened to 1.5 mm at the mouth of the right subclavian artery). I'm very worried. Tell me, is this dangerous and what needs to be done to stop this process? I'm really looking forward to your response. Thank you in advance.

Answer:

Thickening of the intima is not a cause for concern. However, it is advisable to check your blood cholesterol levels.

SUBCLAVIA STEAL SYNDROME honey.

Subclavian steal syndrome is a cessation of blood flow through the branches of the proximal subclavian artery supplying blood to the upper extremities, as a result of which blood enters this section from the arterial circle of the brain, which leads to ischemia of brain tissue; maximum manifestations occur during physical activity.

Etiology

Damage to the vascular wall itself - atherosclerosis (95% of cases), nonspecific arteritis, specific arteritis (in particular, syphilitic)

Pathological tortuosity of arteries, displacement of their mouths, anomalies in the development of the aortic arch

Extra-vasal factors that contribute to compression of the vessel from the outside (accessory cervical ribs, anterior scalene syndrome, etc.).

Clinical picture

Dizziness or lightheadedness (especially during physical exertion), possible blurred vision, hemianopia and ataxia

Muscle weakness in the limb on the affected side

Absence or weakening of the pulse on the affected side.

Diagnostics

Noninvasive measurement of blood pressure in the upper extremities (the difference for unilateral lesions reaches more than 20 mm Hg)

Differential diagnosis

Subclavian artery occlusion

Occlusion of the subclavian artery is a complete closure of the lumen of the subclavian artery, accompanied by insufficient blood supply to the brain and upper extremities. In vascular surgery and cardiology, stenosis and occlusion of the carotid arteries are more common (54-57%). Occlusion of the first segment of the subclavian artery, according to various authors, is found in 3-20% of cases; Moreover, in 17% of cases there are concomitant lesions of the vertebral artery and/or the second segment of the subclavian artery. Bilateral occlusion of the subclavian artery occurs in 2% of cases; the second and third segments of the subclavian artery are affected much less frequently and do not have independent significance in the pathogenesis of cerebrovascular ischemia. Occlusion of the left subclavian artery occurs 3 times more often than the right one.

The subclavian artery is a paired branch of the aortic arch, consisting of the right and left subclavian arteries that supply blood to the upper limbs and neck. The right subclavian artery originates from the brachiocephalic trunk, the left one directly arises from the aortic arch. Topographically, 3 segments are distinguished in the subclavian artery. From the first segment depart the vertebral artery (supplies blood to the spinal cord, muscles and dura mater of the occipital lobes of the brain), internal thoracic artery (provides blood supply to the pericardium, main bronchi, trachea, diaphragm, sternum, anterior and superior mediastinum, pectoral muscles, rectus abdominis ) and the thyrocervical trunk (supplies blood to the thyroid gland, esophagus, pharynx and larynx, muscles of the scapula and neck).

The only branch of the second segment of the subclavian artery (costocervical trunk) supplies blood to the muscles of the neck, cervical and the beginning of the thoracic spine. The branch of the third segment (transverse cervical artery) mainly supplies blood to the back muscles.

Causes of occlusion of the subclavian artery

The main reasons causing occlusion of the subclavian artery are obliterating atherosclerosis. obliterating endarteritis. Takayasu's disease (nonspecific aortoarteritis), post-embolic and post-traumatic obliterations.

Atherosclerosis is the most common cause of occlusive lesions of the aorta and its branches. At the same time, atherosclerotic plaques protruding into the lumen of the vessel are formed in the intima of the arteries. As a result of subsequent sclerosis and calcification of the vascular wall in the area of the affected area, deformation and stenosis of the lumen of the vessel gradually progress, which determine the ischemic stage of atherosclerosis. In some cases, atherosclerotic lesions may be complicated by thrombosis, leading to acute ischemia and necrosis of the blood supplying organ (thrombo-necrotic stage of atherosclerosis). Additional risk factors for atherosclerosis include smoking and arterial hypertension. hypercholesterolemia. diabetes mellitus cardiovascular diseases.

Obliterating endarteritis, as the cause of occlusion of the subclavian artery, is characterized by inflammatory changes in the walls of the arteries, pronounced hyperplastic processes leading to thrombosis and obliteration of blood vessels.

Takayasu's disease, named after the Japanese ophthalmologist. who first described it, can occur with damage to the branches of the aortic arch and the development of aortic aneurysms. coarctation syndrome, aortic insufficiency. renovascular hypertension, abdominal ischemia, pulmonary artery damage, general inflammatory reaction. Nonspecific aortoarteritis most often leads to occlusion of the distal (second-third) segments of the subclavian arteries.

The development of occlusion of the subclavian artery can be facilitated by extravasal compression factors: scars and tumors of the mediastinum. curvature of the cervicothoracic spine, cervical osteochondrosis. neck injuries, fracture of the clavicle and first rib with the formation of excess callus, chest injuries. In some cases, occlusion of the subclavian artery is a consequence of congenital anomalies of the aortic arch and its branches.

In the pathogenesis of disorders arising from occlusion of the subclavian artery, the main role is played by ischemia of the tissues supplied by the affected branch. Thus, when the proximal segment of the subclavian artery is occluded, blood enters its distal segment and upper limb through the vertebral artery, which leads to depletion of the blood supply to the brain. This phenomenon, especially manifested during physical activity, is called steel syndrome or “subclavian steal syndrome.”

The rapid development of occlusion of the subclavian artery, associated with associated thrombosis, leads to cerebral ischemia - acute ischemic stroke.

Symptoms of subclavian artery occlusion

Occlusion of the first segment of the subclavian artery is manifested by one of the characteristic syndromes or a combination of them: vertebrobasilar insufficiency. upper limb ischemia, distal digital embolism or coronary-mammary-subclavian steal syndrome.

Vertebrobasilar insufficiency with occlusion of the subclavian artery it develops in approximately 66% of cases. The clinic of vertebrobasilar insufficiency is characterized by dizziness. headaches, cochleovestibular syndrome (hearing loss and vestibular ataxia), visual disturbances due to ischemic optic neuropathy.

Upper limb ischemia with occlusion of the subclavian artery, it is observed in approximately 55% of patients. During ischemia there are 4 stages:

I – stage of full compensation. Accompanied by increased sensitivity to cold, chilliness, a feeling of numbness, paresthesia, and vasomotor reactions. II – stage of partial compensation. Circulatory failure develops against the background of functional load on the upper limbs. It is characterized by transient symptoms of ischemia - weakness, pain, numbness, coldness in the fingers, hand, and forearm muscles. Transient signs of vertebrobasilar insufficiency may occur. III – stage of decompensation. Circulatory insufficiency of the upper extremities occurs at rest. It occurs with constant numbness and coldness of the hands, muscle wasting, decreased muscle strength, and the inability to perform fine movements with the fingers. IV – stage of development of ulcerative-necrotic changes in the upper extremities. Cyanosis, swelling of the phalanges, cracks, and trophic ulcers appear. necrosis and gangrene of the fingers.

Ischemia of stages III and IV with occlusion of the subclavian artery is rarely detected (6-8% of cases), which is associated with the good development of collateral circulation of the upper limb.

Distal digital embolism with occlusion of the subclavian artery of atherosclerotic origin, it occurs in no more than 3-5% of cases. In this case, ischemia of the fingers occurs, accompanied by severe pain, paleness, coldness and impaired sensitivity of the fingers, and occasionally gangrene.

In patients who have previously undergone mammary coronary bypass surgery. in 0.5% of cases it may develop coronary-mammary-subclavian steal syndrome. In this case, hemodynamically significant stenosis or occlusion of the first segment of the subclavian artery can aggravate cardiac ischemia and cause myocardial infarction.

Diagnosis of occlusion of the subclavian artery

Occlusion of the subclavian artery can be suspected already during a physical examination. If the difference in blood pressure in the upper extremities is >20 mm Hg. Art. one should think of a critical stenosis, and >40 mm Hg. Art. – about occlusion of the subclavian artery. The pulsation of the radial artery on the affected side is weakened or absent. With occlusion of the subclavian artery, a systolic murmur is heard in 60% of patients in the supraclavicular region.

Doppler ultrasound or duplex scanning of the vessels of the upper limb helps to detect occlusion of the subclavian artery in 95% of cases. The criteria for occlusion of the first segment of the subclavian artery are vertebral-subclavian steal syndrome, the presence of collateral blood flow in the distal subclavian artery, the presence of retrograde blood flow along the vertebral artery, and a positive reactive hyperemia test.

Peripheral arteriography allows you to finally determine the diagnosis of occlusion of the subclavian artery and treatment tactics. Using X-ray contrast angiography, the level of occlusion of the subclavian artery, retrograde blood flow through the vertebral arteries, the extent of obliteration, the presence of poststenotic aneurysms, etc. are revealed.

Treatment and prognosis of occlusion of the subclavian artery

Occlusion of the subclavian artery, accompanied by subclavian-vertebral steal syndrome, symptoms of vertebrobasilar insufficiency, and ischemia of the upper limb, is an indication for angiosurgical intervention.

Reconstructive interventions for occlusion of the subclavian artery are divided into:

plastic (endarterectomy, resection with prosthetics, implantation of the subclavian artery into the common carotid); shunting (aorto-subclavian bypass, carotid-subclavian bypass, carotid-axillary bypass, cross subclavian-subclavian bypass); endovascular (dilation and stenting of the subclavian artery, laser or ultrasound recanalization of the subclavian artery).

Due to the high sensitivity of the brain to ischemia and the complexity of the anatomy of the neck, during surgical treatment of occlusion of the subclavian artery, specific complications are possible - intraoperative or postoperative stroke; damage to peripheral nerves with the development of Horner's syndrome, plexitis, paresis of the diaphragm dome, dysphagia; cerebral edema, pneumothorax. lymphorrhea, bleeding.

The prognosis of occlusion of the subclavian artery depends on the nature and extent of damage to the vessel, as well as the timeliness of surgical intervention. Early surgery and good condition of the vessel wall is the key to restoring blood flow in the limb and vertebrobasilar area in 96% of cases.

The subclavian artery is a paired organ that consists of the right and left arteries. It is part of the systemic circulation and begins in the anterior mediastinum. It is from this artery that the blood supply to the arms, neck and organs located in the upper part of the body depends.

Structure

This artery begins in the anterior mediastinum, the right subclavian artery is the final branch of the brachiocephalic trunk, and the left one begins from the aortic arch. In this case, the left subclavian artery is much longer than the right one, and its intrathoracic part is located behind the brachiocephalic vein. This artery goes around the apex of the lung, as well as the dome of the pleura, forming a convex arch. In the area of the first rib, the brachial plexus is located on it. Having bypassed the rib, the artery goes under the collarbone and passes into the axillary artery.

The left and right subclavian arteries have three main sections. The first section begins at the site of its formation and continues to the interscalene space. The second is located in the interscalene space, and the third section of the artery begins near the exit from the interscalene space and ends at the entrance to the axillary cavity.

Functions

Like any other, this artery delivers blood to the organs. Numerous branches of the subclavian artery depart from its first section. One of them is the vertebral artery, which supplies the spinal cord, dura mater of the brain, and muscles. The internal mammary artery originates from the lower surface of the subclavian artery, which supplies blood to the main bronchi, thyroid gland, sternum, diaphragm, tissue of the anterior and superior mediastinum, as well as the rectus abdominis muscle and chest. The thyrocervical trunk arises from the inner edge of the scalene muscle and divides into branches that supply blood to the larynx, muscles of the scapula and neck.

Only one branch departs from the second section of the artery - the costocervical trunk. It supplies blood to the spinal cord, spinal muscles and other muscles. The transverse artery of the neck departs from the third section, which also supplies blood to the muscles of the shoulder and back.

Diseases

The main disease that can affect the branches of the subclavian artery and the artery itself is stenosis or narrowing of the lumen. The most common cause of stenosis is atherosclerotic changes in blood vessels or thrombosis. Sometimes this disease is congenital, but more often acquired. Among the most common causes of subclavian artery stenosis are metabolic disorders in the body, inflammatory diseases and neoplasms. Severe stenosis, leading to decreased blood flow, causes a deficiency of oxygen and nutrients in the tissues. Stenosis can also cause ischemic stroke. With stenosis, patients most often complain of pain from the affected limb. The pain intensifies with physical activity.

Treatment methods

There are several methods for treating subclavian artery stenosis, the main ones being carotid-subclavian bypass and x-ray endovascular stenting. Carotid-subclavian bypass is usually recommended for patients with a hypersthenic physique in whom it is difficult to isolate the first section of the artery. It is also recommended for stenosis in the second section.

X-ray endovascular stenting - treatment through a small incision in the skin 2-3 mm long through a puncture hole. It has great advantages over surgical intervention, as it causes less trauma to the patient.

Left only subclavian artery, a. subclavia, refers to the number of branches extending directly from the aortic arch, while the right one is a branch of the truncus brachiocephalicus. The artery forms an upwardly convex arc that goes around the dome of the pleura. It leaves the chest cavity through the apertura superior, approaches the collarbone, and lies in the sulcus a. subclaviae of the first rib and bends over it. Here the subclavian artery can be pressed to stop bleeding to the first rib behind the tuberculum m. scaleni. Next, the artery continues into the axillary fossa, where, starting from the outer edge of the first rib, it receives the name a. axillaris.

On its way, the subclavian artery passes together with the brachial nerve plexus through the spatium interscalenum, so there are 3 sections distinguished in it: the first - from the point of origin to the entrance to the spatium interscalenum, the second - in the spatium interscalenum and the third - at the exit from it, before the transition to a . axillaris.

Branches of the first section of the subclavian artery (before entering the spatium interscalenum):

A. vertebralis, vertebral artery, the first branch extending upward in the interval between m. scalenus anterior and m. longus colli, goes to the foramen processus transversus of the VI cervical vertebra and rises up through the holes in the transverse processes of the cervical vertebrae to the membrana atlantooccipitalis posterior, perforating which, it enters through the foramen magnum of the occipital bone into the cranial cavity. In the cranial cavity, the vertebral arteries of both sides converge towards the midline and, near the posterior edge of the pons, merge into one unpaired basilar artery, a. basilaris. On its way, it gives off small branches to the muscles, spinal cord and dura mater of the occipital lobes of the brain, as well as large branches:

a. spinalis anterior originates in the cranial cavity near the confluence of two vertebral arteries and goes down and towards the midline towards the artery of the same name on the opposite side, from which it merges into one trunk;
a. spinalis posterior departs from the vertebral artery immediately after it enters the cranial cavity and also goes down the sides of the spinal cord. As a result, three arterial trunks descend along the spinal cord: an unpaired one - along the anterior surface (a. spinalis anterior) and two paired ones - along the posterolateral surface, one on each side (aa. spinales posteriores). All the way to the lower end of the spinal cord they receive reinforcement through the intervertebral foramina in the form of g. spinales: in the neck area - from aa. vertebrales, in the thoracic region - from aa. intercostales posteriores, in the lumbar - from aa. lumbales. Through these branches, anastomoses of the vertebral artery with the subclavian artery and the descending aorta are established;
A. Cerebelli inferior posterior is the largest of the branches of a. vertebralis, begins near the bridge, goes back and, bypassing the medulla oblongata, branches on the lower surface of the cerebellum.

A. basilaris, basilar artery, obtained from the fusion of both vertebrates, unpaired, lies in the median groove of the bridge, at the anterior edge it is divided into two aa. cerebri posteribres (one on each side), which go back and up, go around the lateral surface of the cerebral peduncles and branch on the lower, inner and outer surfaces of the occipital lobe. Taking into account the aa described above. communicantes posteriores from a. carotis interna, posterior cerebral arteries participate in the formation of the arterial circle of the cerebrum, circulus arteriosus cerebri.

From the trunk a. basilaris small branches extend to the pons, into the inner ear, passing through the meatus acusticus internus, and two branches to the cerebellum: a. cerebelli inferior anterior and a. cerebelli superior. A. vertebralis, running parallel to the trunk of the common carotid artery and participating along with it in the blood supply to the brain, is a collateral vessel for the head and neck. Merged into one trunk, a. basilaris, two vertebral arteries and two aa merged into one trunk. spinales anteriores, form an arterial ring, which, along with the circulus arteriosus cerebri, is important for the collateral circulation of the medulla oblongata.

Truncus thyrocervicalis, thyrocervical trunk, departs from a. subclavia upward at the medial edge of m. scalenus anterior, has a length of about 4 cm and is divided into the following branches:

a. thyroidea inferior goes to the posterior surface of the thyroid gland, gives off a. laryngea inferior, which branches in the muscles and mucous membrane of the larynx and anastomoses with a. laryngea superior; branches to the trachea, esophagus and thyroid gland; the latter anastomose with the branches of a. thyroidea superior from the system a. carotis externa;
a. cervicalis ascendens ascends upward along m. scalenus anterior and supplies the deep muscles of the neck; c) a. suprascapularis goes from the trunk downwards and laterally, to the incusura scapulae, and, bending over the lig. transversum scapulae, branches in the dorsal muscles of the scapula; anastomoses with a. circumflexa scapulae.

A. thoracica interna, internal thoracic artery, departs from a. subclavia against the beginning of a. vertebralis, directed downwards and medially, adjacent to the pleura; starting from the first costal cartilage, it runs vertically downwards at a distance of about 12 mm from the edge of the sternum. Having reached the lower edge of the VII costal cartilage, a. thoracica interna is divided into two terminal branches: a. musculophrenica stretches laterally along the line of attachment of the diaphragm, giving branches to it and in the nearest intercostal spaces, and a. epigastrica superior - continues the path of a. thoracica interna downwards, penetrates the vagina of the rectus abdominis muscle and, reaching the level of the navel, anastomoses with a. epigastica inferior (from a. iliaca externa). On its way a. thoracica interna gives branches to the nearest anatomical structures: the connective tissue of the anterior mediastinum, the thymus gland, the lower end of the trachea and bronchi, the six upper intercostal spaces and the mammary gland. Its long branch, a. pericardiacophrenica, together with n. phrenicus goes to the diaphragm, giving branches to the pleura and pericardium along the way. Its rami intercostales anteribres go in the upper six intercostal spaces and anastomose with aa. intercostales posteriores (from the aorta). Branches of the second section of the subclavian artery:

Truncus costocervicalis, costocervical trunk, departs into the spatium interscalenum, goes back and up to the neck of the first rib, where it divides into two branches that penetrate the posterior muscles of the neck and give branches in the canalis vertebralis to the spinal cord and into the first and second intercostal spaces. Branches of the third section of the subclavian artery:

A. transversa colli, transverse artery of the neck, pierces the plexus brachialis, supplies neighboring muscles and descends along the medial edge of the scapula to its lower angle.