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
Fascial spaces of the head and neck superficial temporal and deep temporal spaces. The infratemporal space is the inferior portion of the deep temporal space. The superficial temporal and the deep temporal spaces are sometimes together called the temporal spaces. The masticator spaces are paired structures on either side of the head. The muscles of mastication are enclosed in a layer of fascia, formed by cervical fascia ascending from the neck which divides at the inferior border of the mandible to envelope the area. Each masticator space also contains the sections of the mandibular division of the trigeminal nerve and the internal maxillary artery. The masticator space