Brachiocephalic trunk

At a glance

English

Brachiocephalic trunk

Latin (TA2)

Truncus brachiocephalicus

System

Artery

Region

Trunk

Side

Single, on the midline

About the brachiocephalic trunk

The brachiocephalic trunk, once called the innominate artery, is the first of the three great vessels that leave the arch of the aorta, the other two being the left common carotid and left subclavian arteries. Only the coronary arteries arise from the aorta earlier. It carries blood to the right arm and to the right side of the head and neck, and there is no equivalent trunk on the left, where the carotid and subclavian arteries leave the arch separately.

It begins from the upper convex border of the arch behind the manubrium of the sternum, lying anterior to the other two branches and on their right. It is about 3 to 4 cm long. From there it runs upwards, backwards and to the right, first in front of and then to the right of the trachea, and ends behind the right sternoclavicular joint by dividing into the right subclavian artery and the right common carotid artery.

In the superior mediastinum it lies behind the manubrium, the sternohyoid and sternothyroid muscles, the thymus or its fatty remnant, and the left brachiocephalic vein, which crosses in front of it. The right brachiocephalic vein and the superior vena cava lie to its right, alongside the right pleura, while the trachea lies behind and to the left. Of its two terminal branches, the right subclavian curves laterally over the apex of the lung towards the first rib and the arm, and the right common carotid ascends in the neck to divide into internal and external carotid arteries. It usually gives no other branches, though a small thyroid ima artery comes from it in some people.

Because it crosses in front of the trachea, a tracheostomy placed too low or a cuff that erodes the tracheal wall can damage it, causing major bleeding. The trunk can be narrowed by atherosclerosis or arteritis, producing differences in blood pressure between the arms, and it may be compressed or involved in aortic arch aneurysm and dissection.

Course and supply

Arises from

Arises from the convex upper border of the aortic arch, as its first branch, behind the manubrium.

Ends in

Ends behind the right sternoclavicular joint by dividing into the right subclavian and right common carotid arteries.

Supplies

Carries the arterial supply for the right upper limb and the right side of the head and neck, including part of the brain through the right carotid and vertebral arteries.