Costocervical trunk

The costocervical trunk arises from the upper and back part of the second part of subclavian artery, behind the scalenus anterior on the right side, and medial to that muscle on the left side.

Passing backward, it splits into the deep cervical artery and the superior intercostal artery (highest intercostal artery), which descends behind the pleura in front of the necks of the first and second ribs, and anastomoses with the first aortic intercostal (3rd posterior intercostal artery).