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Schematic of the proximal aorta, frontal view. The brachiocephalic artery (labeled innominate) is the third branch of the aorta and the first branch from the arch of the aorta. The heart in the lower left is not shown.
The veins of the thyroid gland.
|Branches||right common carotid artery
right subclavian artery
thyroid ima artery
There is no brachiocephalic artery for the left side of the body. The left common carotid, and the left subclavian artery, come directly off the aortic arch. However, there are two brachiocephalic veins.
It arises, on a level with the upper border of the second right costal cartilage, from the start of the aortic arch, on a plane anterior to the origin of the left carotid artery; it ascends obliquely upward, backward, and to the right to the level of the upper border of the right sternoclavicular articulation, where it divides into the right common carotid and right subclavian arteries. The artery then crosses the trachea in front of it obliquely from the left to the right, roughly at the middle of the trachea or the level of the ninth tracheal cartilage.
The thyreoidea ima (a. thyreoidea ima) ascends in front of the trachea to the lower part of the thyroid gland, which it supplies.
The innominate artery usually gives off no branches, but occasionally a small branch, the thyreoidea ima, arises from it. Other times, it gives off a thymic or bronchial branch.
It varies greatly in size, and appears to compensate for deficiency or absence of one of the other thyroid vessels. It occasionally arises from the aorta, the right common carotid, the subclavian or the internal mammary.
- Anatomy figure: 21:06-02 at Human Anatomy Online, SUNY Downstate Medical Center