Subclavian artery
Encyclopedia
In human anatomy
, the subclavian arteries are two major arteries of the upper thorax
(chest), below the clavicle (collar bone). They receive blood from the top (arch) of the aorta
. The left subclavian artery supplies blood to the left arm and the right subclavian artery supplies blood to the right arm, with some branches supplying the head and thorax.
The usual branches of the subclavian on both sides of the body are the vertebral artery
, the internal thoracic artery
, the thyrocervical trunk
, the costocervical trunk
and the dorsal scapular artery
. The subclavian becomes the axillary artery
at the lateral border of the first rib
.
, with the anterior scalene (scalenus anterior
) on its anterior side and the middle scalene (scalenus medius
) on its posterior. This is in contrast to the subclavian vein
, which travels anterior to the scalenus anterior.
As the subclavian artery crosses the border of the first rib, it becomes the axillary artery
.
, the left subclavian simply arises from the left 7th intersegmental artery, while the right subclavian arises, proximal to distal:
In order to facilitate the description, each subclavian artery is divided into three parts:
The first portions of the two vessels require separate descriptions; the second and third parts of the two arteries are practically alike.
The origin of the right subclavian from the innominate takes place, in some cases, above the sternoclavicular articulation, and occasionally, but less frequently, below that joint. The artery may arise as a separate trunk from the arch of the aorta, and in such cases it may be either the first, second, third, or even the last branch derived from that vessel; in the majority, however, it is the first or last, rarely the second or third. When it is the first branch, it occupies the ordinary position of the innominate artery; when the second or third, it gains its usual position by passing behind the right carotid; and when the last branch, it arises from the left extremity of the arch, and passes obliquely toward the right side, usually behind the trachea, esophagus, and right carotid, sometimes between the esophagus and trachea, to the upper border of the first rib, whence it follows its ordinary course. In very rare instances, this vessel arises from the thoracic aorta, as low down as the fourth thoracic vertebra. Occasionally, it perforates the Scalenus anterior; more rarely it passes in front of that muscle. Sometimes the subclavian vein passes with the artery behind the Scalenus anterior. The artery may ascend as high as 4 cm. above the clavicle, or any intermediate point between this and the upper border of the bone, the right subclavian usually ascending higher than the left.
The left subclavian is occasionally joined at its origin with the left carotid.
The left subclavian artery is more deeply placed than the right in the first part of its course, and, as a rule, does not reach quite as high a level in the neck. The posterior border of the Sternocleidomastoideus corresponds pretty closely to the lateral border of the Scalenus anterior, so that the third portion of the artery, the part most accessible for operation, lies immediately lateral to the posterior border of the Sternocleidomastoideus.
Human anatomy
Human anatomy is primarily the scientific study of the morphology of the human body. Anatomy is subdivided into gross anatomy and microscopic anatomy. Gross anatomy is the study of anatomical structures that can be seen by the naked eye...
, the subclavian arteries are two major arteries of the upper thorax
Thorax
The thorax is a division of an animal's body that lies between the head and the abdomen.-In tetrapods:...
(chest), below the clavicle (collar bone). They receive blood from the top (arch) of the aorta
Aorta
The aorta is the largest artery in the body, originating from the left ventricle of the heart and extending down to the abdomen, where it branches off into two smaller arteries...
. The left subclavian artery supplies blood to the left arm and the right subclavian artery supplies blood to the right arm, with some branches supplying the head and thorax.
- On the left side of the body, the subclavian comes directly off the arch of aorta.
- On the right side of the body, the subclavian arises from the relatively short brachiocephalic arteryBrachiocephalic arteryThe brachiocephalic artery is an artery of the mediastinum that supplies blood to the right arm and the head and neck....
(trunk) when it bifurcates into the subclavian and the right common carotid arteryCommon carotid arteryIn human anatomy, the common carotid artery is an artery that supplies the head and neck with oxygenated blood; it divides in the neck to form the external and internal carotid arteries. - Structure :...
.
The usual branches of the subclavian on both sides of the body are the vertebral artery
Vertebral artery
The vertebral arteries are major arteries of the neck. They branch from the subclavian arteries and merge to form the single midline basilar artery in a complex called the vertebrobasilar system, which supplies blood to the posterior part of the circle of Willis and thus significant portions of the...
, the internal thoracic artery
Internal thoracic artery
In human anatomy, the internal thoracic artery , previously known as the internal mammary artery , is an artery that supplies the anterior chest wall and the breasts...
, the thyrocervical trunk
Thyrocervical trunk
The thyrocervical trunk is a branch of the subclavian artery arising from the first portion of this vessel, i.e. between the origin of the subclavian artery and the inner border of the scalenus anterior muscle...
, the costocervical trunk
Costocervical trunk
The costocervical trunk arises from the upper and back part of the subclavian artery, behind the scalenus anterior on the right side, and medial to that muscle on the left side....
and the dorsal scapular artery
Dorsal scapular artery
The dorsal scapular artery is a blood vessel which supplies thelevator scapulae, rhomboids, and trapezius.-Origin:...
. The subclavian becomes the axillary artery
Axillary artery
In human anatomy, the axillary artery is a large blood vessel that conveys oxygenated blood to the lateral aspect of the thorax, the axilla and the upper limb...
at the lateral border of the first rib
Rib
In vertebrate anatomy, ribs are the long curved bones which form the rib cage. In most vertebrates, ribs surround the chest, enabling the lungs to expand and thus facilitate breathing by expanding the chest cavity. They serve to protect the lungs, heart, and other internal organs of the thorax...
.
Course
From its origin, the subclavian artery travels laterally, passing between anterior and middle scalene musclesScalene muscles
The scalene muscles are a group of three pairs of muscles in the lateral neck, namely the scalenus anterior, scalenus medius, and scalenus posterior.They are innervated by the spinal nerves C4-C6....
, with the anterior scalene (scalenus anterior
Scalenus anterior
The Scalenus anterior , also known as anterior scalene muscle, lies deeply at the side of the neck, behind the Sternocleidomastoideus.-Anatomy:...
) on its anterior side and the middle scalene (scalenus medius
Scalenus medius
The Scalenus medius, the largest and longest of the three scalene muscles, arises from the posterior tubercles of the transverse processes of the lower six cervical vertebræ. It descendes along the side of the vertebral column to insert by a broad attachment into the upper surface of the first...
) on its posterior. This is in contrast to the subclavian vein
Subclavian vein
The subclavian veins are two large veins, one on either side of the body. Their diameter is approximately that of the smallest finger.-Path:Each subclavian vein is a continuation of the axillary vein and runs from the outer border of the first rib to the medial border of anterior scalene muscle...
, which travels anterior to the scalenus anterior.
As the subclavian artery crosses the border of the first rib, it becomes the axillary artery
Axillary artery
In human anatomy, the axillary artery is a large blood vessel that conveys oxygenated blood to the lateral aspect of the thorax, the axilla and the upper limb...
.
Branches
| Part | Branches | Course |
|---|---|---|
| First part From its origin to the medial border of scalenus anterior Scalenus anterior The Scalenus anterior , also known as anterior scalene muscle, lies deeply at the side of the neck, behind the Sternocleidomastoideus.-Anatomy:... |
Vertebral artery Vertebral artery The vertebral arteries are major arteries of the neck. They branch from the subclavian arteries and merge to form the single midline basilar artery in a complex called the vertebrobasilar system, which supplies blood to the posterior part of the circle of Willis and thus significant portions of the... |
Runs cranially in the transverse foramina Transverse foramen The transverse foramen pierces the transverse processes of the seven cervical vertebrae. In the upper six vertebrae, the foramen gives passage to the vertebral artery, vertebral vein, and a plexus of sympathetic nerves. The seventh foramen lacks the artery, but contains the vein and sympathetic... of the cervical vertebrae Cervical vertebrae In vertebrates, cervical vertebrae are those vertebrae immediately inferior to the skull.Thoracic vertebrae in all mammalian species are defined as those vertebrae that also carry a pair of ribs, and lie caudal to the cervical vertebrae. Further caudally follow the lumbar vertebrae, which also... , joins the vertebral artery on the contralateral side, forming the basilar artery Basilar artery In human anatomy, the basilar artery is one of the arteries that supplies the brain with oxygen-rich blood.The two vertebral arteries and the basilar artery are sometimes together called the vertebrobasilar system, which supplies blood to the posterior part of circle of Willis and anastomoses with... and joins the circle of Willis Circle of Willis The Circle of Willis is a circle of arteries that supply blood to the brain... . |
| Internal thoracic artery Internal thoracic artery In human anatomy, the internal thoracic artery , previously known as the internal mammary artery , is an artery that supplies the anterior chest wall and the breasts... |
Runs caudally behind the ribs, giving off anterior intercostal branches, perforating vessels to the breast Breast The breast is the upper ventral region of the torso of a primate, in left and right sides, which in a female contains the mammary gland that secretes milk used to feed infants.Both men and women develop breasts from the same embryological tissues... and terminating in the superior epigastric artery Superior epigastric artery In human anatomy, superior epigastric artery refers to a blood vessel that carries oxygenated blood and arises from the internal thoracic artery... and the musculophrenic artery |
|
| Thyrocervical trunk Thyrocervical trunk The thyrocervical trunk is a branch of the subclavian artery arising from the first portion of this vessel, i.e. between the origin of the subclavian artery and the inner border of the scalenus anterior muscle... |
Very short. Divides into inferior thyroid artery Inferior thyroid artery The inferior thyroid artery arrises from the thyrocervical trunk and passes upward, in front of the vertebral artery and Longus colli, then turns medially behind the carotid sheath and its contents, and also behind the sympathetic trunk, the middle cervical ganglion resting upon the... , suprascapular artery Suprascapular artery The suprascapular artery is a branch of the thyrocervical trunk.-Course:At first, it passes downward and laterally across the scalenus anterior and phrenic nerve, being covered by the sternocleidomastoid muscle; it then crosses the subclavian artery and the brachial plexus, running behind and... and transverse cervical artery Transverse cervical artery The transverse cervical artery is a branch of the thyrocervical trunk, running at a higher level than the suprascapular artery.-Path:... |
|
| Second part Lying behind scalenus anterior |
Costocervical trunk Costocervical trunk The costocervical trunk arises from the upper and back part of the subclavian artery, behind the scalenus anterior on the right side, and medial to that muscle on the left side.... |
Splits into highest intercostal artery Highest intercostal artery The highest intercostal artery is an artery in the human body that usually gives rise to the first and second posterior intercostal arteries, which supply blood to their corresponding intercostal space... and deep cervical artery Deep cervical artery -Course:It arises, in most cases, from the costocervical trunk, and is analogous to the posterior branch of an aortic intercostal artery: occasionally it is a separate branch from the subclavian artery.... . |
| Dorsal scapular artery Dorsal scapular artery The dorsal scapular artery is a blood vessel which supplies thelevator scapulae, rhomboids, and trapezius.-Origin:... |
From either second or third part. Passes backwards to supply levator scapulae and rhomboids. | |
| Third part Between the lateral border of scalenus anterior and the outer border of the first rib First rib The first rib is the most curved and usually the shortest of all the ribs; it is broad and flat, its surfaces looking upward and downward, and its borders inward and outward.... |
Embryology
EmbryologicallyEmbryology
Embryology is a science which is about the development of an embryo from the fertilization of the ovum to the fetus stage...
, the left subclavian simply arises from the left 7th intersegmental artery, while the right subclavian arises, proximal to distal:
- aortic archAortic archThe arch of the aorta or the transverse aortic arch is the part of the aorta that begins at the level of the upper border of the second sternocostal articulation of the right side, and runs at first upward, backward, and to the left in front of the trachea; it is then directed backward on the left...
IV - right dorsal aortaDorsal aortaEach primitive aorta receives anteriorly a vein—the vitelline vein—from the yolk-sac, and is prolonged backward on the lateral aspect of the notochord under the name of the dorsal aorta....
(between the 4th and the 7th intersegmental arteries) - right 7th intersegmental artery
Anatomical details
On the right side the subclavian artery arises from the brachiocephalic (innominate) artery behind the right sternoclavicular articulation; on the left side it springs from the arch of the aorta. The two vessels, therefore, in the first part of their course, differ in length, direction, and relation with neighboring structures.In order to facilitate the description, each subclavian artery is divided into three parts:
- The first portion extends from the origin of the vessel to the medial border of the Scalenus anterior.
- The second lies behind this muscle.
- The third extends from the lateral margin of the muscle to the outer border of the first rib, where it becomes the axillary artery.
The first portions of the two vessels require separate descriptions; the second and third parts of the two arteries are practically alike.
First Part of the Right Subclavian Artery
The first part of the right subclavian artery arises from the innominate artery, behind the upper part of the right sternoclavicular articulation, and passes upward and lateralward to the medial margin of the Scalenus anterior. It ascends a little above the clavicle, the extent to which it does so varying in different cases.Relations
It is covered, in front, by the integument, superficial fascia, Platysma, deep fascia, the clavicular origin of the Sternocleidomastoideus, the Sternohyoideus, and Sternothyreoideus, and another layer of the deep fascia. It is crossed by the internal jugular and vertebral veins, by the vagus nerve and the cardiac branches of the vagus and sympathetic, and by the subclavian loop of the sympathetic trunk which forms a ring around the vessel. The anterior jugular vein is directed lateralward in front of the artery, but is separated from it by the Sternohyoideus and Sternothyreoideus. Below and behind the artery is the pleura, which separates it from the apex of the lung; behind is the sympathetic trunk, the Longus collie and the first thoracic vertebra. The right recurrent nerve winds around the lower and back part of the vessel.First Part of the Left Subclavian Artery
The first part of the left subclavian artery arises from the arch of the aorta, behind the left common carotid, and at the level of the fourth thoracic vertebra; it ascends in the superior mediastinal cavity to the root of the neck and then arches lateralward to the medial border of the Scalenus anterior.Relations
It is in relation, in front, with the vagus, cardiac, and phrenic nerves, which lie parallel with it, the left common carotid artery, left internal jugular and vertebral veins, and the commencement of the left innominate vein, and is covered by the Sternothyreoideus, Sternohyoideus, and Sternocleidomastoideus; behind, it is in relation with the esophagus, thoracic duct, left recurrent nerve, inferior cervical ganglion of the sympathetic trunk, and Longus colli; higher up, however, the esophagus and thoracic duct lie to its right side; the latter ultimately arching over the vessel to join the angle of union between the subclavian and internal jugular veins. Medial to it are the esophagus, trachea, thoracic duct, and left recurrent nerve; lateral to it, the left pleura and lung.Second Part of the Subclavian Artery
The second portion of the subclavian artery lies behind the Scalenus anterior; it is very short, and forms the highest part of the arch described by the vessel.Relations
It is covered, in front, by the skin, superficial fascia, Platysma, deep cervical fascia, Sternocleidomastoideus, and Scalenus anterior. On the right side of the neck the phrenic nerve is separated from the second part of the artery by the Scalenus anterior, while on the left side it crosses the first part of the artery close to the medial edge of the muscle. Behind the vessel are the pleura and the Scalenus medius; above, the brachial plexus of nerves; below, the pleura. The subclavian vein lies below and in front of the artery, separated from it by the Scalenus anterior.Third Part of the Subclavian Artery
The third portion of the subclavian artery runs downward and lateralward from the lateral margin of the Scalenus anterior to the outer border of the first rib, where it becomes the axillary artery. This is the most superficial portion of the vessel, and is contained in the subclavian triangle.Relations
It is covered, in front, by the skin, the superficial fascia, the Platysma, the supraclavicular nerves, and the deep cervical fascia. The external jugular vein crosses its medial part and receives the transverse scapular, transverse cervical, and anterior jugular veins, which frequently form a plexus in front of the artery. Behind the veins, the nerve to the Subclavius descends in front of the artery. The terminal part of the artery lies behind the clavicle and the Subclavius and is crossed by the transverse scapular vessels. The subclavian vein is in front of and at a slightly lower level than the artery. Behind, it lies on the lowest trunk of the brachial plexus, which intervenes between it and the Scalenus medius. Above and to its lateral side are the upper trunks of the brachial plexus and the Omohyoideus. Below, it rests on the upper surface of the first rib.Peculiarities
The subclavian arteries vary in their origin, their course, and the height to which they rise in the neck.The origin of the right subclavian from the innominate takes place, in some cases, above the sternoclavicular articulation, and occasionally, but less frequently, below that joint. The artery may arise as a separate trunk from the arch of the aorta, and in such cases it may be either the first, second, third, or even the last branch derived from that vessel; in the majority, however, it is the first or last, rarely the second or third. When it is the first branch, it occupies the ordinary position of the innominate artery; when the second or third, it gains its usual position by passing behind the right carotid; and when the last branch, it arises from the left extremity of the arch, and passes obliquely toward the right side, usually behind the trachea, esophagus, and right carotid, sometimes between the esophagus and trachea, to the upper border of the first rib, whence it follows its ordinary course. In very rare instances, this vessel arises from the thoracic aorta, as low down as the fourth thoracic vertebra. Occasionally, it perforates the Scalenus anterior; more rarely it passes in front of that muscle. Sometimes the subclavian vein passes with the artery behind the Scalenus anterior. The artery may ascend as high as 4 cm. above the clavicle, or any intermediate point between this and the upper border of the bone, the right subclavian usually ascending higher than the left.
The left subclavian is occasionally joined at its origin with the left carotid.
The left subclavian artery is more deeply placed than the right in the first part of its course, and, as a rule, does not reach quite as high a level in the neck. The posterior border of the Sternocleidomastoideus corresponds pretty closely to the lateral border of the Scalenus anterior, so that the third portion of the artery, the part most accessible for operation, lies immediately lateral to the posterior border of the Sternocleidomastoideus.
See also
- Aberrant subclavian arteryAberrant subclavian arteryAberrant subclavian artery, or aberrant subclavian artery syndrome refers to a rare anatomical variant of the origin of the right or left subclavian artery...
- Subclavian steal syndromeSubclavian steal syndromeIn medicine, subclavian steal syndrome , also called subclavian steal phenomenon or subclavian steal steno-occlusive disease, is a constellation of signs and symptoms that arise from retrograde flow of blood in the vertebral artery or the internal thoracic artery, due to a proximal stenosis ...
- Thoracic outlet syndromeThoracic outlet syndromeThoracic outlet syndrome is a syndrome involving compression at the superior thoracic outlet involving compression of a neurovascular bundle passing between the anterior scalene and middle scalene...