Succlavia - Artery Succlavia of A.Griguolo

Generality

The subclavian artery is the equal artery, located in the upper part of the thorax, which, with the help of different branches, supplies blood to the encephalon, thorax, neck, shoulder and upper limb.

The subclavian can be qualified as an asymmetric artery, since, in the right half of the human body, it is born in a different point than where it originates in the left half. In fact, while on the right it originates from the brachiocephalic trunk (the first large-caliber branch of the aorta), on the left it originates directly from the aorta.

Provided with different branches, the subclavian artery follows a course that leads it, first, to pass behind the anterior scalene muscle and, subsequently, to transform, approximately at the level of the upper margin of the 1st rib, into an axillary artery.

Short review of what an artery is

In human anatomy, any blood vessel used for transporting blood from the heart to the body's various tissues and organs is included in the list of arteries .

Contrary to what many people think, only oxygenated blood (ie "load" of oxygen) does NOT flow in the arteries; to demonstrate what has just been stated is the existence of the pulmonary artery and its branches, ie the arterial vessels destined to transport oxygen-poor blood from the heart to the lungs, in order to provide oxygenation of the aforementioned blood.

What is the Succlavia?

The subclavian, or subclavian artery, it is the large and even asymmetrical artery, located in the upper part of the thorax, below the clavicle, which has the important task of directing the flow of oxygenated blood in districts such as the brain, the thorax, the neck, shoulder and upper limb.

As an equal anatomical element, the subclavian is present, more or less in the same position, both on the right half and on the left half of the human body. The subclavian of the right half of the human body is called the right subclavian artery, while the subclavian of the left half of the human body is called the left subclavian artery .

As can be guessed, the right subclavian artery directs the blood supply in the direction of the aforementioned districts present to the right of the human body (therefore brain of the right half, neck of the right half, etc.); the left subclavian artery, on the other hand, directs the blood supply to the aforementioned districts on the left side of the human body.

What does it mean that the subclavian is asymmetrical?

The subclavian artery is defined as asymmetric because, on the right side of the body, it has a different origin, compared to the left side of the body.

This asymmetry will obviously be investigated in the following chapter.

Important clarification

In anatomy, the term "subclavian" is used only for the subclavian artery.

This clarification is important, because in the human body there is also the subclavian vein, which however is called always and only with the name just mentioned (for which it is impossible to confuse).

Anatomy

To simplify the description of the subclavian, anatomists have the habit of ideally dividing the arterial vessel in question into 3 portions (or sections), which are:

The initial portion or portion of origin . This section of the subclavian artery runs from the origin to the medial border of the scalene muscle;
The intermediate portion or second portion . This section includes the part of the subclavian which flows behind the scalene muscle;
The final portion or third portion . This subclavian tract runs from the lateral margin of the scalene muscle to the outer edge of the first rib.

The initial portion varies - as anticipated - from right to left, while the intermediate and final portions are practically overlapping on both sides of the body.

In the next sections of this chapter, the article will discuss, in detail, the various portions of the subclavian artery and its branches; moreover, it will give information about the blood circulation inside the subclavian (from who receives the blood and where it takes it).

Initial portion of the left subclavian artery

On the left side of the human body, the subclavian originates from the aortic arch, to be precise from the final section of the aortic arch, slightly later than where the left carotid artery arises.

Preceded by the so-called ascending aorta (ascending because oriented upwards), the aortic arch is the second section of the aorta . As the name suggests, this aorta section has an arched shape.

Its diameter is between 2 and 3 centimeters, while its length does not exceed 5 centimeters.

At the end of its course begins the so-called descending aorta (descending, because oriented downwards).

Starting from the aortic arch, therefore, the left subclavian ascends in the direction of the upper portion of the mediastinal cavity, leading to the root of the neck, above the cervical pleura, and, when it is in a lateral position with respect to the medial margin of the scalene muscle anterior to the left, a curvature begins, which later will orient it towards the left upper limb.

It is with this principle of curvature, in the aforementioned position with respect to the anterior scalene muscle, which ends the original portion of the left subclavian artery.

Did you know that ...

The left subclavian artery is born at the same height as the 4th thoracic vertebra .

REPORTS OF THE INITIAL PORTION OF THE LEFT SUCCLAVIA ARTERY

Opposite, the left subclavian is related to the left vagus nerve, the left cardiac nerve, the left phrenic nerve, the left common carotid artery, the left internal jugular vein, the left vertebral vein and the sternotiroid, sternocleidomastoid and sternoioidis side muscles left.
Later, the left subclavian tightens the esophagus, the thoracic duct, the left recurrent nerve, the inferior cervical ganglion of the sympathetic trunk and the long muscle of the left neck.
In the medial position, the left subclavian artery is related to the esophagus (*), the thoracic duct (*), the left recurrent nerve (*) and the trachea.
In the lateral position, the left subclavian artery tightens with the pleura and the left lung.

(*) NB : Esophagus, thoracic duct and left recurrent nerve are located behind the left subclavian artery only in the very first section of the latter; in fact, when the artery in question arches, the aforementioned structures assume a medial position.

Initial portion of the right subclavian artery

On the right side of the human body, however, the subclavian arises from the so-called brachiocephalic trunk (or anonymous artery ).

The brachiocephalic trunk is the very first branch of the aorta. Its precise point of origin is on the initial part of the already mentioned aortic arch.

1.5 cm in diameter and no more than 3.5 cm long, the brachiocephalic trunk ends its course with a branch, which leads to the generation of the right common carotid artery and to the subclavian in question.

Starting from the brachiocephalic trunk, the right subclavian artery ascends to the top of the cervical pleura and, when it is lateral to the medial margin of the right anterior scalene muscle, a curvature begins, which will then direct it towards the right upper limb.

As with the left subclavian artery, it is with the beginning of this curvature, in the aforementioned position with respect to the anterior scalene muscle, that the original portion of the right subclavian ends.

Did you know that ...

The right subclavian artery is born at the right sternoclavicular joint . The right sternoclavicular joint is the joint that joins the right clavicle to the sternum .

REPORTS OF THE INITIAL PORTION OF THE RIGHT SUCCLAVIAN ARTERY

Frontally, the right subclavian is related to the superficial cervical fascia, the deep cervical fascia, the platysma muscle, the clavicular tendons of the sternotiroid, sternocleidomastoid and sternoioid muscles of the right side of the body, the right vagus nerve, the right cardiac nerve, the right right internal jugular vein and the right vertebral vein.
Later, the right subclavian artery tightens with the long muscle of the right neck, the first thoracic vertebra and the right recurrent nerve.
Inferior and posteriorly, the right subclavian is related to the right pleura and the right lung.

Intermediate portion

Subsequent to the initial portion described above, the intermediate portion of the subclavian is the portion of the latter that passes behind the anterior scalene muscle. It is very short and, continuing the curvature begun in the previous section, represents its apex (this means that, after the intermediate portion, the subclavian artery will tend to proceed downwards).

The conclusion of the intermediate portion of the subclavian is the overcoming of the lateral margin of the anterior scalene muscle.

REPORTS OF THE INTERMEDIATE PORTION OF THE SUCCLAVIA

Frontally, the intermediate portion of the subclavian is related to the superficial cervical fascia, the platysma muscle, the deep cervical fascia, the sternocleidomastoid muscle, the anterior scalene muscle and the phrenic nerve.
At the rear, the intermediate portion of the subclavian clenches relationships with the pleura and the middle scalene muscle.
Above, the intermediate portion of the subclavian artery is related to the brachial plexus.
Below, the intermediate portion of the subclavian artery builds relationships with the subclavian vein and (once again) with the pleura.

Final portion

Beginning immediately after the lateral margin of the anterior scalene muscle, the final portion of the subclavian is the latter portion of the latter.

Including the terminal part of the curvature begun in the original portion, it is consequently oriented downwards and, to be precise, towards the upper limb.

The path of the final portion of the subclavian ends at the outer edge of the 1st rib .

At the 1st rib, the subclavian becomes an axillary artery .

REPORTS OF THE FINAL PORTION OF THE SUCCLAVIA

On the front, the final portion of the subclavian area has relationships with the superficial cervical fascia, the platysma muscle, the supraclavicular nerves, the deep cervical fascia, the external jugular vein, the transverse scapular vein, the transverse cervical vein, the anterior jugular vein, the muscle subclavian and clavicle.
Later, the final portion of the subclavian is related to the lower trunk of the brachial plexus.
Latero-superiorly, the final portion of the subclavian artery tightens with the upper trunk of the brachial plexus and the homoioid muscle.
Below, the final portion of the subclavian artery is related to the upper surface of the 1st rib.

Branches of the subclavian

The branches of an artery are its branches .

The subclavian artery from which, in each of its parts, at least one branch is born.

BRANCHE OF THE INITIAL PORTION

The branches of the initial portion of the subclavian artery are three: the vertebral artery, the internal thoracic artery and the thyrocervical trunk .

The vertebral artery is directed towards the vertebral column, to be precise towards the foramen the sixth and the seventh cervical vertebra; after which, it encounters the contralateral vertebral artery, generating the basilar artery, and contributes to the constitution of the anastomosis known as Willis's polygon .

The internal thoracic artery follows a path opposite to the vertebral artery and, in fact, runs behind the sternum and the rib cage; along the way, it gives rise to three smaller branches, which are: the upper epigastric artery, the pericardiophrenic artery and the musculofrenic artery .

Finally, the thyrocervical trunk lacks a defined path, as it soon branches into 4 smaller arteries, which are: the inferior thyroid artery, the suprascapular artery, the ascending cervical artery and the transverse cervical artery .

BRANCA OF THE INTERMEDIATE PORTION

The intermediate portion of the subclavian has a single branch: the so-called costocervical trunk .

The costocervical trunk has a relatively short course; in fact, it soon divides into two smaller vessels (sub-branches), which are the upper intercostal artery and the deep cervical trunk ; the upper intercostal artery is directed towards the intercostal spaces and the back, while the deep cervical trunk is directed towards the neck.

FINAL PORTION BRANCA

Like the intermediate portion, the final portion of the subclavian also has a branch only: the so-called dorsal scapular artery .

The dorsal scapular artery follows a path through which it passes near the upper trunk of the brachial plexus.

Did you know that ...

Very often, the dorsal scapular artery is a branch of the transverse cervical artery.

Therefore, instead of being born in the final portion of the subclavian, it is born in the previous portion.

Blood circulation in the subclavian artery

The subclavian receives blood from the aorta; after all, it is a branch of the latter or in any case it is very close to it.

Then, it diffuses the incoming blood towards its branches and in the axillary artery, placed at its conclusion.

From the axillary artery, the blood proceeds in the direction of the brachial artery, which with its branches takes care of oxygenating bones and soft tissues of the arm, forearm and hand.

Function

Through its innumerable branches and sub-branches, the subclavian supplies the posterior part of the brain, the cerebellum, the back of the neck, the upper limbs and the antero-superior portion of the thorax with oxygenated blood.

Branches of the subclavian artery	Which anatomical districts supply oxygenated blood?
Vertebral artery	The posterior cranial fossa, the occipital lobes and a part of the vertebral column.
Internal thoracic artery	Through the superior epigastric artery, the sheath of the right muscles of the abdomen. Through the pericardiophrenic artery, the pericardium (with the help of the frene artery). Through the musculofrenic artery, the upper part of the diaphragm.
Thyrocervical trunk	Through the inferior thyroid artery, the larynx, the trachea, the esophagus, the thyroid, the parathyroid, the infraioid muscles and the prevertebral muscles. Through the suprascapular artery, the upper scapular muscles. Through the ascending cervical artery, some lateral muscles of the upper neck and part of the spine. Through the transverse cervical artery, the trapezius.
Costocervical trunk	Through the upper intercostal artery, the two upper intercostal spaces, the neck and back muscles, the back skin and the vertebral canal. Through the deep cervical trunk, the deep musculature of the neck.
Dorsal scapular artery	The levator scapula and rhomboid muscles.