aortic dissection

noun

: a pathological splitting of the middle layer (media) of the aorta following penetration of blood through the inner layer (intima)

Early symptoms of aortic dissection are similar to those of a heart attack: severe, persistent chest pain of sudden onset but with the pain moving to the back and occasionally to the abdomen and hips.

—Allen Douma, The Chicago Tribune

Aortic dissection classically begins with a tear in the aortic intima that exposes a diseased medial layer to the systemic pressure of intraluminal blood.

—Eric M. Isselbacher, in Cecil Textbook of Medicine, 22nd edition