The Anatomy of the Brachiocephalic Artery

The brachiocephalic (innominate) artery is a thick-walled blood vessel that originates from the aortic arch, the top part of the aorta—the main vessel that carries blood from the heart. It brings blood to the right carotid artery in your neck and the right subclavian artery, which supplies blood to the right arm.

The brachiocephalic is so named because blood flows through it to the arm (brachio) and the head (cephalic). It is also known as the brachiocephalic trunk, as it is the base for two other important arteries.

This article discusses the anatomy of the brachiocephalic artery. It also looks at its function and clinical significance.

Anatomy

The brachiocephalic lies above the aortic arch and below the thymus gland, which is behind the breastbone. The trachea (windpipe) sits right between the brachiocephalic artery and the left common carotid in the neck.

This artery is only about 4 to 5 centimeters (cm) in length. It starts where the ascending aorta begins to curve into the aortic arch, just at the midline.

The brachiocephalic artery follows the right side of the trachea up to the level where the clavicle (collarbone) meets the sternum (breastbone). It ends where it divides into the right subclavian artery and the right carotid artery. 

Anatomical Variations

Some people are born with a different variation of the aortic arch, which affects the structure of the brachiocephalic artery. This variation is called a bovine arch. It occurs in as much as 27% of the population and is more common in African-Americans.

In a bovine arch, the branches of the brachiocephalic artery and the left common carotid artery originate together from the aortic arch, rather than separately.

On an X-ray, the structure looks a little like the head of a cow with horns (hence the name bovine arch). There are two additional variations of this that are much less common.

Most anatomical variations of the brachiocephalic artery don't cause any symptoms. However, they can come into play during surgical or endovascular interventions in the chest. They pose a greater risk of rupture and ischemia (restricted circulation) during surgical procedures in the chest.

It's important to let your doctor know if you have an anatomical variation of the brachiocephalic artery, especially if surgery is being considered.

Function

The brachiocephalic artery carries blood from the aorta (the largest artery in the body) to the right side of the brain and the right arm. This is a large blood vessel that provides most of the blood flow to these areas.

The brachiocephalic artery only supplies blood to the right arm and the right side of the brain.

(The left common carotid artery supplies blood to the left side of the brain. The left subclavian artery supplies blood to the left arm. Those two arteries aren't combined. They both arise along the aortic arch apart from the brachiocephalic artery.)

Some cases of bypass surgery go around the brachiocephalic artery so that blood can be carried directly from the aortic arch to the carotid artery. In these cases, the overflow of blood into the carotid can stimulate the receptors that sense pressure changes. This can trigger a significant fall in blood pressure.

Clinical Significance

The brachiocephalic artery can sometimes have a buildup of fatty plaque that causes narrowing (stenosis) and restricts blood flow to the upper extremities. Brachiocephalic stenosis can cause pain in the right arm with exercise, vision problems, and transient ischemic attacks (TIAs), also called mini-strokes.

Narrowing of the blood vessels that's further downstream can lead to a condition called subclavian steal syndrome, which "steals" blood flow away from the brain and pushes it to the arm.

Subclavian steal syndrome can cause neurological symptoms similar to a stroke. It's usually worse during exercise with the affected arm since it causes the arm to pull more blood flow.

Narrowing and blockages of the brachiocephalic artery are often referred to as innominate artery disease. It can be treated through various surgical methods.

• Endarterectomy is a surgical procedure used to remove plaque from the inside of arteries. It is often used on the carotid arteries to prevent stroke.
• Angioplasty is the use of a balloon inflated inside narrowed arteries to force them open. Once an artery is open, a stent is placed to hold it in that position. A stent is a medical device that looks a bit like a small spring.
• Bypass surgery takes a segment of another blood vessel and grafts it to a point proximal (upstream) and distal (downstream) to the blockage. It allows blood to flow around (bypass) the blockage in the brachiocephalic artery.

An aneurysm in the brachiocephalic artery is rare but clinically significant. The brachiocephalic artery is the location of 3% of all supra-aortic aneurysms, which branch from the aortic arch.

These aneurysms can grow and put pressure on surrounding tissues and structures, causing difficulty swallowing or shortness of breath. They can also create blood clots that might travel downstream to other locations.

Doctors usually treat a brachiocephalic artery aneurysm through surgical repair.

Summary

The brachiocephalic artery is attached to the aortic arch. It branches into the right subclavian artery and the right carotid artery. It supplies blood to the right side of the brain and to the right arm.

Blockages of the brachiocephalic artery are referred to as innominate artery disease. This condition can cause pain in the arm with exercise, vision problems, and mini-strokes. It can be treated with various surgeries to remove plaque, open the artery, or bypass the blockage.