Brachiocephalic trunk

Last revised by Henry Knipe on 2 Feb 2022

The brachiocephalic trunk (BCT) (also known as the brachiocephalic artery, and previously as the innominate artery) is the first branch of the aortic arch and supplies the head, neck and right arm.

Although sometimes described as such, the brachiocephalic trunk is not one of the great vessels.

The brachiocephalic trunk is the first and rightmost of the three main branches of the aortic arch. It measures 4-5 cm in length with a diameter of 12.1 ± 1.6 mm. 

After arising in the midline, it courses upwards to the right, crossing the trachea and bifurcates posterior to the right sternoclavicular joint, into the right subclavian and right common carotid arteries. It has no other branches. 

See also variant anatomy of the aortic arch for a more general discussion of such variants.

The brachiocephalic artery originates from incorporation by the right fourth aortic arch and persistence of a proximal additional part of the right fourth innominate artery, leading to elongation of the artery 2.

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Cases and figures

  • Figure 1: Aortic arch normal anatomy (illustration)
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  • Case 1a: labeled 25
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  • Case 1b: labeled 42
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  • Case 1c: labeled 39
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  • Figure 2: mediastinum (Gray's illustration)
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