<prompt> Which of the following sinus is related with middle ear cavityEthmoidCavernousTransverseSigmoid  <response>: i.e. Sigmoid sinus: 714,686 - Snell 8thSigmoid sinus are a direct continuation of the transverse sinuses. Each sinus turns downward behind the mastoid antrum of the temporal bone and then leaves the skull through the jugular foramen to become the internal jugular vein. The posterior wall of the mastoid antrum is related to the sigmoid venous sinus. If the infection spreads in this direction a thrombosis in the sigmoid sinus may take place 714 - Snell 8th 