Assertion: fourth aortic arch | /r/CapableOf | join as single descending aorta
Facets:
Source sentences:
text: This anomaly is caused by persistence of the right and left embryonic fourth aortic arches, which results in formation of a vascular ring from the splitting of the ascending aorta into two limbs that pass to either side of the trachea and esophagus 5 (both of which get encircled), which then join as a single descending aorta.