The elastic cartilage of the ear lacks blood vessels; instead, it relies on the adjacent perichondrium (layer of tissue surrounding cartilage), which contains blood vessels, for its nourishment.
Physical trauma to the ear from activities such as boxing, rugby, etc., cause blood to accumulate between the cartilage and the perichondrium. Consequently, the underlying cartilage is deprived of its nourishment and overtime new cartilage regenerates from the perichondrium in an irregular manner.
The end result is an enlarged, protruding and irregular ear that resembles a cauliflower – cauliflower ear.
Macdonald DJM, Calder N, Perrett G, McGuiness RG: Case presentation: a novel way of treating acute cauliflower ear in a professional rugby player. Br J Sports Med, 2005 39(6): e29. Go to reference