Surgical image taken through a left thoracotomy shows a blue vessel loop around the ligamentum arteriosum which was compressing the esophagus posterior to it. The red vessel loops are around the right aortic arch (on the right) and the left subclavian artery (on the left). The vascular ring was subsequently divided by division of the ligamentum arteriosum. The vascular ring then sprang open dramatically, relieving its compression upon the esophagus.