is when an oxygen-carrying blood vessel (artery) is perforated (slightly torn along its length).
Think perforated paper if you want an example. The kind that's easy to tear in the middle, down the perforation.
Arterial perforation is generally a dangerous condition and a medical emergency... many patients will feel severe pain
in the area of the perforation (normally the perforation occurs in a high pressure area like the aorta
, going from the top to the bottom of the torso). Again, this is a medical emergency, and if anybody suspects they have it, they must seek help immediately.