Human Anatomy Part 2 - K. A. Diubenko, A. K. Kolomiitsev, Yu. B. Chaikovsky 2008

Special Part
Cardiovascular system, systema cardiovasculare - Special Part
Blood vessels of the systemic circulation - Arteries of the head and neck - Subclavian artery

The Subclavian Artery, a. subclavia (Fig. 23 A, 30), (a paired vessel) is the main trunk supplying the upper limb. The left subclavian arises from the aortic arch, while the right arises from the brachiocephalic trunk, truncus brachiocephalicus (Fig. 22, 31). The left subclavian artery is longer than the right. The subclavian artery arches over the apex of the lung and exits the thoracic cavity through the superior thoracic aperture, apertura thoracis superior. Together with the brachial nerve plexus, the subclavian artery passes through the interscalene space, spatium interscalenum, where it lies in the subclavian groove, sulcus a. subclavia, of the first rib. Here, the artery can be compressed against the scalene tubercle, tuberculum m. scaleni, for temporary arrest of bleeding from the upper limb.

Topographically and anatomically, three segments of the artery are distinguished: the first—prior to entering the spatium interscalenum; the second—directly within the spatium interscalenum; and the third—from the exit of the spatium interscalenum to the Water/144.html">Origin of the axillary artery, a. axillaris.

Branches of the first segment:

1. Vertebral artery, a. vertebralis;

2. Internal thoracic artery, a. thoracica interna;

3. Thyrocervical trunk, truncus thyreocervicalis.

1. The vertebral artery, a. vertebralis* (Fig. 32), is the first branch originating from the subclavian artery before the latter enters the interscalene space. It courses superiorly and enters the transverse foramen, foramen transversarium, of the sixth cervical vertebra. It then passes through the transverse foramina of the six cervical vertebrae and reaches the atlas, where it lies in the vertebral artery sulcus, sulcus arteriae vertebralis. Afterwards, it pierces the posterior atlanto-occipital membrane, membrana atlantooccipitalis, the dura mater, and enters the cranial cavity through the foramen magnum. Within the cranial cavity, near the lower border of the Pons, the two vertebral Arteries unite to form the Basilar artery, a. basilaris. Along its course, a. vertebralis gives off a series of small branches to the Deep Muscles of the Neck, the Spinal Cord, its Meninges, and the Cerebellum. In addition to these small branches, three major branches arise from the vertebral artery:

1. Anterior spinal artery, a. spinalis anterior, branches off near the junction of the vertebral arteries and runs to meet the corresponding artery of the opposite side, with which they form a single trunk;

2. Posterior spinal artery, a. spinalis posterior, branches off from the vertebral artery immediately after its entry into the cranial cavity, and then descends along the lateral surface of the spinal cord.

3. Posterior inferior cerebellar artery, a. cerebelli inferior posterior, originates from the vertebral artery near the pons, curves around the Medulla Oblongata, and ramifies on the Inferior surface of the cerebellum.

2. The basilar artery, a. basilaris (Fig. 27, 32), an unpaired vessel, originates near the lower border of the pontine Brain, lies in the basilar sulcus of the pons, and divides near its upper border into two posterior cerebral arteries, aa. cerebri posteriores. The posterior cerebral arteries course posteriorly, curve around the cerebral peduncles laterally, and ramify On the surface of the occipital lobe. They supply the occipital and temporal lobes, the nuclei of the hemispheres, and the cerebral peduncles, and participate in The formation of the choroid plexus and the cerebral arterial circle, circulus arteriosus cerebri. The basilar artery gives off branches to the pons, the Inner ear, and the cerebellum (the anterior inferior cerebellar artery, a. cerebelli inferior anterior, and the superior cerebellar artery, a. cerebelli superior). The terminal segments of the two vertebral arteries and the two anterior spinal arteries form a rhombus-shaped arterial circle on the anterior surface of the medulla oblongata (Zakharchenko, 1911)** (Fig. 27, 32). The arterial circle (of Zakharchenko) is of great importance for collateral Circulation. Individual variations of Zakharchenko's arterial circle are observed (S. M. Ognev, 1950; D. B. Bekov, S. S. Mikhailov, 1979) (Fig. 32 A).

3. The internal thoracic artery, a. thoracica interna (Fig. 22, 33), originates from the subclavian artery opposite the vertebral artery, passes into the thoracic cavity, where it runs at a distance of 1–2 cm from the lateral margin of the Sternum down to the lower border of the seventh costal Cartilage. Along its course, it supplies the Thymus, Bronchi, Pericardium, Diaphragm, and mammary gland, and also sends branches (anterior intercostal branches, rr. intercostales anteriores) to the first six intercostal spaces, which anastomose with the posterior intercostal branches, rr. intercostales posteriores (Branches of the Thoracic Aorta, aorta thoracica). At the level of the lower border of the seventh costal cartilage, the internal thoracic artery divides into several branches: the pericardiacophrenic artery, a. pericardiacophrenica; the musculophrenic artery, a. musculophrenica; and the superior epigastric artery, a. epigastrica superior. The superior epigastric artery enters the rectus abdominis sheath, Vagina m. recti abdominis, where it forms an intersystemic anastomosis (Fig. 33) in the umbilical region, regio umbilicalis, with the inferior epigastric artery, a. epigastrica inferior (a branch of the external iliac artery, a. iliaca externa), while the pericardiacophrenic artery reaches the diaphragm and gives off branches to the Pleura and pericardium.

* Four parts (segments) are distinguished in the vertebral artery: the prevertebral part, pars prevertebralis; the cervical part, pars cervicalis; the atlanto-axial part, pars atlantica; and the intracranial part, pars intracranialis. Knowledge of these segments is of major clinical significance.

** Mykhailo Oleksiyovych Zakharchenko (1879–1953) was a prominent neuropathologist, professor, and Honored Scientist of the Uzbek SSR (1933). He described the rhomboid arterial polygon on the anterior surface of the medulla oblongata and proposed naming it the bulbar arterial circle, circulus arteriosus bulbaris.

Class="center">

Fig. 32. Subclavian artery, a. subclavia; vertebral artery, a. vertebralis; and basilar artery, a. basilaris (after Toldt)

Fig. 32 A. Zakharchenko's arterial circle. Diagram of Variants of the bulbar arterial circle according to D. B. Bekov

1, 2 — Formation of the arterial bulbar rhombus by both vertebral arteries; 3 — symmetrical arterial bulbar circle; 4 — anastomoses of the anterior spinal arteries; 5 — reticular form of the bulbar arterial circle; 6 — formation of the bulbar arterial circle by three branches; 7, 8 — absence of the bulbar arterial circle (up to 54%); 9 — formation of the bulbar circle by separated vertebral arteries; 10 — absence of the bulbar arterial circle and separated vertebral arteries

4. The thyrocervical trunk, truncus thyreocervicalis (Fig. 34), arises from the superior surface of the subclavian artery near the medial border of the anterior scalene Muscle, m. scalenus anterior, courses superiorly, and divides into three branches: 1) the inferior thyroid artery, a. thyreoidea inferior, supplying The Thyroid Gland, with branches to the Pharynx, Esophagus, Trachea, and Larynx; 2) the ascending cervical artery, a. cervicalis ascendens, which supplies the deep Muscles of the neck and the spinal cord; 3) the suprascapular artery, a. suprascapularis, which passes through the lateral cervical triangle and, above the scapular notch, incisura scapulae, enters the supraspinous fossa, fossa supraspinata, where it supplies the dorsal muscles of the scapula.

Branches of the second segment:

1. The costocervical trunk, truncus costocervicalis, arises from the posterior surface of the subclavian artery, a. subclavia, within the interscalene space, spatium interscalenum. The trunk courses toward the HEAD of the first rib, where it divides into branches:

1. The deep cervical artery, a. cervicalis profunda, which supplies the deep Neck Muscles and the spinal cord;

2. The supreme intercostal artery, a. intercostalis suprema, which runs to the First and Second intercostal spaces.

Branches of the third segment:

1. A. transversa colli, the transverse cervical artery, branches off the subclavian artery immediately after the latter exits the interscalene space. The transverse cervical artery passes between the branches of the Brachial Plexus and heads toward the infraspinous fossa, where it supplies Blood to the scapular and back muscles.

* In cases of hypoplasia of the inferior thyroid arteries, which occurs in 10% of cases, the ima thyroid artery serves as an accessory source. It originates from the aortic arch and ascends along The surface of the trachea—a clinically significant anatomical variant, as it is vulnerable to injury during tracheostomy (V. V. Kupriyanov, N. V. Voskresensky).