In medical terminology, Battle's sign, also mastoid ecchymosis, is an indication of fracture of the base of the posterior portion of the skull, and may suggest underlying brain trauma. Battle's sign consists of bruising over the mastoid process, as a result of extravasation of blood along the path of the posterior auricular artery.. The sign is named after William Henry Battle.
- Naumann, Hans Heinz; Jan Helms (1998). Head and neck surgery. Thieme. pp. 154. ISBN 0865776601. http://books.google.com/books?id=MK1brjp6gaEC&pg=PA154&lpg=PA154&dq=%22battle's+sign%22+vein&source=bl&ots=6AWfA_t1Im&sig=BjxQ9-_yu4bxBjr6JhEXbtz-VfE&hl=en&ei=BRduSvixDYio8gTe--GMDQ&sa=X&oi=book_result&ct=result&resnum=9.