part of part of has part has part characteristic of inheres in has modifier Descending thoracic aorta aneurysm Fusiform descending thoracic aortic aneurysm 2014-03-23T02:26:12Z Aneurysm is considered a severe form of dilatation. Dilatation of the fusiform descending thoracic aorta A concentric abnormal localized widening (dilatation) of the descending thoracic aorta that involves the full circumference of the vessel wall UMLS:C4022753 HP:0012728 aneurysm abnormal increased amount fusiform descending thoracic aorta