Protruding jugular bulb presenting as a middle ear mass. A case report.

Protrusion of the jugular bulb is an uncommon but important cause of a bluish-purple mass behind the tympanic membrane. A knowledge of this condition is necessary to prevent massive haemorrhage following tympanotomy or during temporal bone surgery. The diagnosis can be established by jugular venography, which demonstrates the protrusion of the characteristic knuckle of the jugular bulb into the middle ear cavity.