[[False aneurysm]]s, also known as a [[pseudoaneurysm]], requires all three [[layer]]s of the [[arterial wall]] wall to be disrupted, and integrity of the [[vessel]] is only maintained by associated [[hematoma]] or surrounding connective tissue
((McElroy KM, Malone RJ, Freitag WB, Keller I, Shepard S, Roychowdhury S. Traumatic pseudoaneurysm of the basilar artery. Am J Phys Med Rehabil. 2008;87:690–691. doi: 10.1097/PHM.0b013e31817fbaea.)).

In true [[aneurysm]]s, the [[adventitia]] is preserved.