The aorta (aorta) is the largest vessel in the human body.
It gives rise to all the arteries of the systemic circulation.
It has the following parts:
The ascending aorta (pars ascendens aortae)
The arch of the aorta (arcus aortae)
The descending aorta (pars descendens aortae)
Three major arteries arise from the arch:
The brachiocephalic trunk (truncus brachiocephalicus)
The left common carotid artery (arteria carotis communis sinistra)
The left subclavian artery (arteria subclavia sinistra)
The right subclavian artery (arteria subclavia dextra) arises from the brachiocephalic trunk.
In this video, we will consider the anatomy of the subclavian artery and its branches, as well as its areas of blood supply
The subclavian artery (arteria subclavia)
Passes from the thoracic cavity through its superior aperture, circumflexes the dome of the pleura, and, together with the brachial plexus, is located in the interscalene space. Then it passes under the clavicle, crosses the first rib in the groove of the subclavian artery and below the lateral margin of the first rib penetrates into the axillary fossa, where it passes into the axillary artery (a. axillaris).
Topographically, in relation to the scalenus anterior muscle, it is divided into three parts:
1) The prescalene part, which is located from the place of origin to the internal border of the anterior scalenus muscle;
2) The interscalene part, which is located in the interscalene gap, behind the anterior scalenus muscle
3) The postscalene part, which begins after the exiting from the interscalene gap.
It supplies the cervical spinal cord and membranes, the brain stem, the occipital and temporal lobes of the cerebral hemispheres, as well as a number of muscles with blood.
It has a number of branches supplying the skin of the chest and superior part of the abdomen, as well as the internal organs of the thoracic cavity with blood
Let’s consider the branches according to the topography.
The following arteries arise from the trunk of the subclavian artery in the prescalene part:
The vertebral artery (arteria vertebralis), which arises at the level of the transverse process of the seventh cervical vertebra.
It has several parts:
the prevertebral part follows between the anterior scalenus muscle and the longissimus cervicis muscle
the cervical part passes superiorly through the foramina of the transverse processes of the cervical vertebrae six to two
the atlantic part turns laterally and passes through a foramen in the transverse process of the atlas
the intracranial part circumflexes the back of the superior articular surface of the atlas, passes through the posterior atlanto-occipital membrane and the dura mater of the spinal cord, and enters the cranial cavity through the foramen magnum
Spinal branches (rami spinales), heading to the spinal cord through the intervertebral foramina, and muscular branches (rami musculares), which supply the deep muscles of the neck with blood, arise from the cervical part of the vertebral artery.
The following branches arise from the intracranial part of the vertebral artery:
- Anterior and posterior meningeal branches (rami meningei anterior et posterior), which supply the dura mater of the brain with blood;
- The posterior spinal artery (arteria spinalis posterior), which circumflexes the medulla oblongata and descends along the anterior surface of the spinal cord, where it widely anastomoses with the artery of the same name on the opposite side;
- The anterior spinal artery (arteria spinalis anterior), which communicates with the artery of the same name on the opposite side and forms an unpaired vessel following down in the anterior fissure of the spinal cord
- The posterior inferior cerebellar artery (arteria inferior posterior cerebelli), which circumflexes the medulla oblongata and supplies the posteroinferior parts of the cerebellum with blood.
The basilar artery (arteria basilaris) is formed at the posterior border of the pons, where the right and left vertebral arteries communicate.
At the anterior border of the pons, the basilar artery divides into two posterior cerebral arteries, which are involved in the formation of the cerebral arterial circle.
The following arteries arise from the basilar artery:
The right and left anterior inferior cerebellar arteries (arteria inferior anterior cerebelli, dextra et sinistra), which supply the inferior parts of the cerebellum with blood
- The right and left labyrinthine arteries (arteriae labyrinthi dexter et sinister), which pass through the internal auditory canal to the internal ear together with the vestibulocochlear nerve;
Pontine arteries (arteriae pontis), which supply the pons with blood;
- Mesencephalic arteries (arteriae mesencephalicae), which pass to the midbrain;
- The right and left superior cerebellar arteries (arteria superior cerebelli, dextra et sinistra), which pass to the superior parts of the cerebellum
The posterior cerebral artery (arteria cerebri posterior) is a paired terminal branch of the basilar artery, which passes in the posterior and superior direction, laterally to the brain stem, circumflexing it.
It supplies blood to the occipital lobe and inferior part of the temporal lobe of the cerebral hemisphere, basal nuclei, midbrain, diencephalon, and cerebral peduncles with blood. The posterior communicating artery, a branch of the internal carotid artery, ends by the posterior cerebral artery.
On the base of the brain, due to the fusion of the anterior cerebral (from the internal carotid artery system), posterior connective, and posterior cerebral arteries (from the vertebral artery system), an arterial cerebral circle, also known as the circle of Willis (circulus arteriosus cerebri), is formed.
The posterior communicating artery communicates the posterior cerebral artery with the internal carotid artery on each side.
The anterior part of the cerebral arterial circle is closed by the anterior communicating artery located between the right and left anterior cerebral arteries, arises respectively from the right and left internal carotid arteries.
The internal thoracic artery (arteria thoracica interna) arises from the inferior semicircle of the subclavian artery medial to the entrance to the interscalene space.
The artery follows vertically down the posterior surface of the anterior chest wall at the edge of the sternum, adjacent to the cartilages of ribs 1 to 8. The internal thoracic artery gives off many branches:
- Mediastinal branches (rami mediastinales) supply the fiber and lymph nodes of the superior and anterior mediastinum, as well as the mediastinal pleura with blood;
- Thymic branches (rami thymici) – supply the thymus with blood;
- Bronchial and tracheal branches (rami bronchiales et tracheales) – supply the inferior part of the trachea and the main bronchus of their side;
- The pericardiacophrenic artery (arteria pericardiacophrenica) arises at the level of the 1st rib and descends along the lateral surface of the pericardium together with the phrenic nerve, supplies this nerve and diaphragm with blood, widely anastomosing with branches of arteries supplying the diaphragm with blood
- Sternal branches (rami sternales) – supply the sternum with blood. The branches of the right and left sides anastomose with each other
- Perforating branches (rami perforantes) pass to the pectoralis major muscle and the skin of the anterior chest wall in the area of five to six superior intercostal spaces.
At the same time, the medial mammary branches (rami mammarii mediales) arise from branches 3 to 5
The anterior intercostal branches (rami intercostales anteriores) are located in the corresponding intercostal spaces and supply the muscles of the same name with blood.
- The terminal branches of the internal thoracic artery are the musculophrenic artery (arteria musculophrenica), which passes down to the diaphragm, and along its course it gives off branches that supply the intercostal muscles of the five inferior intercostal spaces with blood
- The superior epigastric artery (arteria epigastrica superior) penetrates the posterior wall of the rectus sheath and passes along the posterior surface of this muscle, which it supplies with blood.
The branches of the artery anastomose with the branches of the inferior epigastric artery (from the external iliac artery).
The thyrocervical trunk (truncus thyrocervicalis) is short (about 1.5 cm), thick, arises from the subclavian artery at the level of the medial border of the anterior scalene muscle.
The trunk immediately divides into three branches going to the muscles and organs.
- The inferior thyroid artery (arteria thyroidea inferior), which passes superiorly along the anterior surface of the longissimus cervicis muscle.
Going to the thyroid gland, it supplies it with blood. This artery gives off the following branches: pharyngeal (rami pharyngeales), esophageal (rami oesophageales), tracheal (rami tracheales), as well as the inferior laryngeal artery (arteria laryngea inferior), which anastomoses with the superior laryngeal artery under the lamina of the thyroid cartilage;
- The suprascapular artery (arteria suprascapularis), which pases behind the clavicle to the suprascapular notch.
- The transverse cervical artery (arteria transversa cervicis), which passes posteriorly between the trunks of the brachial plexus.
The branches of the transverse cervical artery widely anastomose with the branches of the occipital artery (from the external carotid artery) and the posterior intercostal arteries (from the branch of the thoracic aorta).
Only one artery arises from the trunk of the subclavian artery in the interscalene part. This is the costocervical trunk.
The costocervicalis trunk (truncus costocervicalis) arises from the posterior semicircle of the subclavian artery in the interscalene space.
Next, this trunk passes posteriorly and superiorly to the neck of the 1st rib and gives off the deep cervical and supreme intercostal arteries.
- The deep cervical artery (arteria cervicalis profunda) passes between the first rib and the transverse process of the seventh cervical vertebra posteriorly, and supplies the semispinalis muscles of the head and neck with blood;
- The supreme intercostal artery (arteria intercostalis suprema) passes down in front of the neck of the 1st rib into the intercostal spaces.
There, the first and second posterior intercostal arteries (arteriae intercostales posteriores prima et secunda) arise from it.
The postscalene part also usually has only one branch called the dorsal scapular artery (arteria dorsalis scapulae).
It supplies blood to the muscles of the superior part of the back and shoulders, including the trapezius muscle, levator scapulae muscle, and rhomboid muscles.
The subclavian arteryand its branches
- Subclavian artery
- a. subclavia
- Vertebral artery
- a. vertebralis
- Anterior and posteriormeningeal branches
- rr. meningei anterior et posterior
- Posterior spinal artery
- a. spinalis posterior
- Anterior spinal artery
- a. spinalis anterior
- Posterior inferior cerebellar artery
- a. inferior posteriorcerebelli
- Basilar artery
- a. basilaris
- Right and left anterior inferior cerebellar arteries
- a. inferior anterior cerebelli dextra et sinistra
- Right and left labyrinthine arteries
- aa. labyrinthi dexter etsinister
- Pontine arteries
- aa. pontis
- Mesencephalic arteries
- aa. mesencephalicae
- Right and left superiorcerebellar arteries
- a. superior cerebelli dextra et sinistra
- Posterior cerebral artery
- a. cerebri posterior
- Internal thoracic artery
- a. thoracica interna
- Mediastinal branches
- rr. mediastinales
- Thymic branches
- rr. thymici
- Bronchial and tracheal branches
- rr. bronchiales et racheales
- Pericardiacophrenic artery
- a. pericardiacophrenica
- Sternal branches
- rr. sternales
- Perforating branches
- rr. perforantes
- Medial mammary branches
- rr. mammarii mediales
- Anterior intercostal branches
- rr. intercostales anteriores
- Musculophrenic artery
- a. musculophrenica
- Superior epigastric artery
- a. epigastrica superior
- Thyrocervical trunk
- truncus thyrocervicalis
- Inferior thyroid artery
- a. thyroidea inferior
- Transverse cervical artery
- a. transversa cervicis
- Costocervical trunk
- truncus costocervicalis
- Deep cervical artery
- a. cervicalis profunda
- Supreme intercostal artery
- a. intercostalis suprema
- Dorsal scapular artery
- a. dorsalis scapulae