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 Alliance cancer, which is attributed to advanced stage disease at the time of diagnosis. Early detection is imperative for increasing chances of survival. Free screening clinics for head and neck cancers during Oral, Head and Neck Cancer Awareness week, sponsored by the Head and Neck Cancer Alliance, provides opportunities for earlier diagnosis of malignant cancer. Screenings for oral, head and neck cancer are generally available via your local physician, dentist and other healthcare facilities. The Head and Neck Cancer Alliance offers free screenings nationwide;free screenings are offered predominantly during Oral, Head and Neck Cancer Awareness Week in April at healthcare events