Subclavian Artery

The subclavian arteries are paired with the main arteries of the upper thorax, under the clavicle, in human anatomy. Receiving blood from the aortic arch, the right subclavian artery passes blood to the right arm, and the left part of the artery passes the blood to the left arm, with some branches passing the blood to the thorax and head. On the left part of the body, the artery comes right off the aortic arch. When it bifurcates into the subclavian and the right joint carotid artery, it arises from the comparatively small brachiocephalic artery on the right side.

The natural subclavian artery branches on both sides of the body are the thyrocervical trunk, the vertebral artery, the costocervical trunk, the internal thoracic artery, and the dorsal scapular artery that might branch off the transverse cervical artery, a branch of the thyrocervical trunk. Subsequently, making it the axillary artery at the oblique edge of the prime rib.

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Subclavian Artery Anatomy

The subclavian artery passes right between the middle and anterior scalene muscles, with the middle scalene on its posterior side and the anterior on its anterior side. This is right opposite to the subclavian vein, traveling anterior to the scalenus anterior. It becomes an axillary artery when it passes through the oblique edge of the prime rib. On the left side, the subclavian artery springs from the aorta arch while it arises from the brachiocephalic artery on the right side, present right behind the right sternoclavicular articulation. 

Hence, both vessels differ in length, relation with other structures, direction, and one another on the first part of their course. The left subclavian artery has a standard measure of 9 cm in adults, the right subclavian artery measures around 6 cm, while both have a 9-12 mm width. 

Parts of Subclavian Artery 

Each subclavian artery has three distinct parts and functions. 

• The first part of the subclavian artery is the prescalene, it stretches right from the origin of the vessel to the scalenus anterior muscles' medial border. 

• The second part of the subclavian artery is the scalene, lying right behind the anterior muscle of the scalenus.  

• The third and last part of the subclavian artery is the post scalene. It stretches from the lateral margin of the muscle to the oblique edge of the prime rib, where it becomes the axillary artery. 

First Part

Right Subclavian Artery

The initial section of the right subclavian artery arises from the brachiocephalic trunk present at the rear section of the upper part of the right sternoclavicular articulation. The right subclavian artery branches upward and alongside the scalenus anterior muscle's medial margin and rises a little over the medial portion of the clavicle.

Covered by superficial fascia, deep fascia, the clavicular origin of the sternocleidomastoid muscle, the sternothyroid muscle, the integument, the platysma muscle, the platysma muscle, the sternohyoid muscle, and another layer of the deep fascia in the front. The right subclavian artery branches are traversed by the vertebral vein and the internal jugular vein. 

Left Subclavian Artery

The initial section of the left subclavian artery emerges from the aortic arch present right behind the left common carotid artery, at the level of the fourth thoracic vertebra. It sprouts in the higher mediastinal cavity to the source of the neck and then bends sidewards to the scalenus anterior muscle's medial border. 

It is connected to the cardiac nerves, the phrenic nerves, which lie laterally with it, the vagus nerve, the left common carotid artery, the genesis of the left innominate vein, and left internal jugular and vertebral veins. 

Second Part

The second division of the subclavian artery prevails following the scalenus anterior muscle and in the face of the scalenus medius muscle. Despite being short, this division makes the highest part of the arch defined by the vessel. It is covered by the skin, the platysma muscle, the sternocleidomastoid muscle, the deep cervical fascia, the superficial fascia, and the scalenus anterior muscle on the front. 

Third Part

The third and the last section of the subclavian artery moves to descend and sidelong from the parallel margin of the scalenus anterior muscle to the external border of the prime rib, where it converts into the axillary artery. This is the most external part of the vessel present in the subclavian triangle. This portion is covered by the superficial fascia, the supraclavicular nerves, the skin, the platysma muscle, and the deep cervical fascia.

Subclavian Artery Branches 

There are five major subclavian artery branches: 

• The internal thoracic artery

• The costocervical trunk

• The vertebral artery

• The thyrocervical trunk; and

• The dorsal scapular artery.

Functions of Subclavian Artery

The principal function of the subclavian artery is to distribute oxygen-rich blood to specific areas of the upper body. The two parts of the subclavian arteries supply oxygen-rich blood on either side of the body. Further, the arteries also supply oxygenated blood to the neck and upper limbs, the chest wall's upper and front region, and the largest part of the brain, the cerebrum. 

Did You Know?

• Did you know the second and third parts of the subclavian artery are practically alike?

• Did you know the subclavian artery anatomy varies in their origin, course, and height to which they rise in the neck?

• Did you know the right subclavian artery branches the vertebral artery, supplier of blood to the brainstem, spinal cord, and other posterior parts of the brain?

• Did you know damage to the recurrent laryngeal nerve can lead to hoarseness, which could be perpetual?