In anatomy, a reference to the area around the "tunica adventitia" of a blood vessel: In the lecture, the students were informed about the periadventitial veins and arteries in a person's body.

The adventitia is the outermost connective tissue covering any organ, vessel, or other structure not covered by a serosa. The covering is properly derived from outside, that is from the surrounding connective tissue and does not form an integral part of such an organ or a structure.