Battle's sign, also postauricular ecchymosis, indicative of a base of skull fracture (fractura basis cranii). It consists of bruising immediately behind the ears due to the presence of blood accumulating beneath the fascia, producing discoloration at the tip of the mastoid.

Another common bruising sign of a skull injury is raccoon eyes, the purplish discoloration around the eyes following fracture of the frontal portion of the skull base.

This sign is named after William Henry Battle.