Age/sex: 29-year-old male
Size: 12.0 x 15.5 x 5.3 cm
The specimen shows an aortic arch (A) with trachea (T) behind. The brachiocephalic (B) and common carotid (C) arteries are well seen; only the origin of the left subclavian artery (S) is evident. Beginning at this vessel, there is an accumulation of blood between the inner and outer parts of the descending aortic wall that extends about 5 cm along its length (long arrows). A tear can be seen in the intima just below its origin (short arrow).
Aortic dissection
This frequently fatal condition occurs following a tear in the inner lining (intima) of the aorta. The disruption allows blood to flow from the aortic lumen into the middle of its wall (media) where it continues for a variable distance “dissecting” the wall in two. In many cases, blood re-enters the aortic lumen through a second tear farther down. In others, it extends proximally towards the heart and ruptures into the pericardial sac causing tamponade (compression) of the heart and sudden death (see Specimen 46).
The intimal tear is most often seen in the ascending aorta, in which case its cause is usually not evident. A tear just beyond the subclavian artery, such as seen in this specimen, is often associated with severe chest trauma.
Below: Diagram illustrating the mechanism of aortic dissection. Blood begins to flow between the tunica intima and the tunica media due to a tear in the intima, or inner wall.
Source: Figure 1. The structure of an aortic wall. From “Current understanding of aortic dissection,” by X Yuan, A Mitsis, and CA Nienaber. (2022). Life 12(10).
