Emissary veins passing through the foramen ovale, jugular foramen, foramen lacerum, and hypoglossal canal. Because the emissary veins are valveless, they are an important part in selective brain cooling through bidirectional flow of cooler blood from the evaporating surface of the head. In general, blood flow is from external to internal but the flow can be altered by increased intracranial pressure. A type of emissary vein goes through the sphenoidal emissary foramen inferior to the zygomatic arch with the cavernous sinus on the inside of the skull. This is an important route for spread of infection because cranial nerve VI and the
Head and neck cancer and Epstein-Barr virus. Head and neck cancers are most commonly of the squamous cell carcinoma type. The diagnosis is confirmed by tissue biopsy. The degree of spread may be determined by medical imaging and blood tests. Not using tobacco or alcohol can reduce the risk for head and neck cancer. While screening in the general population does not appear to be useful, screening high risk groups by examination of the throat might be useful. Head and neck cancer often is curable if it is diagnosed early; however, outcomes are typically poor if it is diagnosed late. Treatment may include a