What clinical sign is characterized by bluish discoloration behind the ears?

The clinical sign characterized by bluish discoloration behind the ears is known as Battle's sign. This phenomenon is typically associated with a basilar skull fracture, which may occur from trauma, such as a head injury. The discoloration is due to the pooling of blood in the tissues behind the ears, particularly in the mastoid area, as a result of the fracture disrupting blood vessels.

Recognizing Battle's sign is crucial in acute care settings since it helps in identifying potential cranial or vertebral injuries. This sign, along with other indicators like raccoon eyes (periorbital ecchymosis), serves as important diagnostic clues in determining the extent of head trauma and guiding further imaging and treatment options.