Which vascular anomaly will exhibit a complete vascular ring?
1.Right aortic arch aberrant left subclavian with a left ligamentum arteriosum
2.Right aortic arch , aberrant left subclavian with a left ligamentum arteriosum
3.Left aortic arch,aberrant right subclavian
4.Pulmonary sling
sol:
a. The most common symptomatic vascular ring is the double aortic arch. The second most common vascular ring is the right aortic arch, aberrant left subclavian with a left ligamentum arteriosum.
b. In this malformation, the aorta ascends from the heart anterior to the tracheal bifurcation, to arch over the right mainstem bronchus. It then descends posterior to the esophagus and trachea. The left subclavian comes off the descending aorta.
c. The ligamentum arteriosum (remnant of the ductus arteriosus) connects the left subclavian or descending aorta (depending on its origin) to the left pulmonary artery.
d. The trachea and esophagus are encircled by the ascending aorta anteriorly, the aortic arch on the right, the descending aorta posteriorly, and the ligamentum arteriosum and the left pulmonary artery on the left. This results from persistence of the right dorsal aorta, regression of the left dorsal aorta and regression at the left 4th aortic arch.
e. Due to the regression of the 4th arch, the left subclavian develops from the right descending aorta. 10% of this type of ring will have associated intracardiac defects.