Left subclavian artery only, a. subclavia, refers to the number of branches extending from the aortic arch directly, while the right branch is the branch of truncus brachiocephalicus.
The artery forms a convex upward arc, enveloping the dome of the pleura. She leaves the chest cavity through apertura superior, approaches the collarbone, lies down in sulcus a. subclaviae I ribs and bends over it. Here, the subclavian artery can be pressed to stop bleeding to the I rib behind tuberculum m. scaleni. Then the artery continues into the axillary fossa, where, starting from the outer edge of the I rib, it is called a. axillaris On its way, the subclavian artery goes along with the brachial nerve plexus through the spatium interscalenum, so there are 3 sections: the first is from the beginning to the entrance to the spatium interscalenum, the second is in the spatium interscalenum and the third is at the exit from it, before going to a . axillaris
The branches of the first division of the subclavian artery (before entering the spatium interscalenum):
1. A. vertebralis, vertebral artery, the first branch extending upward between m. scalenus anterior and m. longus colli, is sent to the foramen processus transversus VI of the cervical vertebra and rises up through the holes in the transverse processes of the cervical vertebrae to the membrana atlantooccipitalis posterior, which, through the foramen magnum of the occipital bone, enters the cranial cavity. In the cranial cavity, the vertebral arteries of the one and the other sides converge to the midline and merge into one unpaired basilar artery near the posterior edge of the bridge, a. basilaris. On its way, it gives small branches to the muscles, spinal cord and hard shell of the occipital lobes of the brain, as well as large branches:
a) a. spinalis anterior departs in the cavity of the skull near the confluence of two vertebral arteries and goes down and to the midline towards the artery of the same side of the opposite side, from which it merges into one trunk;
b) a. The spinalis posterior departs from the vertebral artery immediately after it enters the cranial cavity and is also directed down the sides of the spinal cord. As a result, three arterial trunks descend along the spinal cord: unpaired – on the front surface (a. Spinalis anterior) and two paired – on the posterolateral surface, one on each side (aa. Spinales posteriores). All the way to the lower end of the spinal cord, they receive reinforcements in the form of rr through the intervertebral holes. spinales: in the neck – from aa. vertebrales, in the thoracic – from aa. intercostales posteriores, in lumbar – from aa. lumbales. Through these branches, the anastomoses of the vertebral artery are established with the subclavian artery and the descending aorta;
c) a. Cerebelli inferior posterior is the largest of the branches a. vertebralis, starts near the bridge, goes back and, bypassing the medulla oblongata, forks on the lower surface of the cerebellum.
A. basilaris, the basilar artery, is obtained from the fusion of both vertebrates, unpaired, lies in the median sulcus of the bridge, at the front edge of it is divided into two aa. cerebri posteriores (one on each side), which are directed back and up, bend around the lateral surface of the legs of the brain and branch out on the lower, inner and outer surfaces of the occipital lobe. Taking into account the above aa. communicantes posteriores from a. carotis interna, posterior cerebral arteries are involved in the formation of the arterial circle of the brain, circulus arteriosus cerebri. From the trunk a. The basilaris branch off small branches to the bridge, into the inner ear, passing through meatus acusticus internus, and two branches to the cerebellum: a. cerebelli inferior anterior and a. cerebelli superior.
A. vertebralis, which runs parallel to the trunk of the common carotid artery and participates 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 fused into one trunk. spinales anteriores, form the arterial ring, which, along with the circulus arteriosus cerebri – the Willisian arterial circle, is important for the collateral circulation of the medulla.
2. Truncus thyrocervicalis, the thymus, moves away from a. subclavia up at the medial edge m. The scalenus anterior, has a length of about 4 cm and is divided into the following branches: a)
a. thyroidea inferior goes to the posterior surface of the thyroid gland, renders 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 branches a. thyroidea superior from system a. carotis externa;
b) a. cervicalis ascendens rises above m. scalenus anterior and supplies deep neck muscles;
c) a. The suprascapularis goes from the trunk downwards and laterally to the incusura scapulae, and bending over lig. transversum scapulae, branched in the dorsal muscles of the scapula; anastomoses with a. circumflexa scapulae.
3. A. thoracica interna, internal artery moving away from a. subclavia versus beginning a. vertebralis, goes down and medially, adjacent to the pleura; starting from the I rib cartilage, goes vertically downwards at a distance of about 12 mm from the edge of the sternum. Reaching the bottom edge of VII rib cartilage, a. thoracica interna is divided into two final branches: a. musculophrenica stretches laterally along the line of attachment of the diaphragm, giving to it both the nearest intercostal spaces of the branch and a. epigastrica superior – continues the way a. down thoracica interna, penetrates the vagina of the rectus abdominis muscle and, reaching the level of the navel, anastomose with a. epigastica inferior (from a. iliaca externa).
On the way a. thoracica interna gives branches to the nearest anatomical structures: connective tissue of the anterior mediastinum, thymus gland, lower end of the trachea and bronchi, to the six upper intercostal spaces and the mammary gland. Its long branch, a. pericardiacophrenica, together with n. phrenicus goes to the diaphragm, giving branches along the path to the pleura and pericardium. Her rami intercostales anteriores run in the upper six intercostal spaces and anastomose with aa. intercostales posteriores (from the aorta).