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The emissary veins connect the veins outside the cranium with the intracranial venous sinuses and can be seen at embryonic stage 7. Each individual may have a varied number of the various emissary veins. Various authors have posited that these structures equalize intracranial pressure. These structures may communicate with the diploic veins. Herein, the anatomy and clinical significance of these structures are reviewed.

Publisher Summary This chapter discusses the epidemiology, etiology, pathogenesis, clinical features, diagnosis, and management of suppurative intracranial thrombophlebitis. Septic intracranial venous sinus thrombosis arises as a consequence of infection in the paranasal sinuses and less frequently following infections of the middle ear or mastoid. The most common isolate from the cases of septic intracranial venous thrombosis associated with pericranial infections is Staphylococcus aureus . Suppurative intracranial thrombophlebitis is most frequently the result of pericranial infection. The local infection causes septic thrombophlebitis of veins draining the infected area, with subsequent intracranial extension of the infected thrombus along emissary veins. The cavernous sinuses are the structures most frequently involved in septic venous sinus thrombosis. The transverse sinuses are the second most frequent intracranial venous sinuses to be involved by septic processes. The advent of magnetic resonance imaging (MRI) and then of computed tomography (CT) angiography and venography revolutionized diagnosis of both venous sinus and cortical vein thrombosis, such that MRI and CT venography are currently the diagnostic procedures of choice in detecting venous sinus thrombosis.

The radiator hypothesis focuses on differential effects that natural selection had on the vascular physiology of hominins that occupied separate niches and the consequences for brain evolution in Paranthropus, Australopithecus, and Homo. Comparative studies of emissary foramina suggest that the network of cranial veins of the australopithecine ancestors of Homo began to increase in complexity in response to temperature constraints associated with occupying niches in thermally stressful habitats. This venous network subsequently became elaborated in Homo in conjunction with increasing brain size. Because physiologists have shown that emissary veins participate in selective brain cooling by delivering blood cooled at the head’s surface into the braincase, the radiator hypothesis postulates that the elaborate network of cranial veins contributed to the regulation of brain temperature as it coevolved with brain size during hominin evolution. The radiator hypothesis has been controversial for two basic reasons: First, it has implications for hominin phylogeny, which is always a contentious subject in paleoanthropology. Second, the subject of selective brain cooling in humans has been controversial within the physiological community. New findings are discussed that bear on selective brain cooling and the radiator hypothesis.

Publisher Summary This chapter discusses the risks and injuries in combat spots. In boxing, the main target of attack, that is, the head, and the instrument of attack, that is, the hand, are the commonest sites of injury. Injuries to other parts of the body are rare. Head injuries are the commonest cause of death and serious disability. For this reason, amateur boxing is usually restricted to three rounds as compared to the professional sport where fights last 10–15 rounds because of public demand. After a boxer has been knocked out, he is not permitted to fight for a 4-week period. Both amateur and professional boxers need to be medically examined before re-entering the ring, and in the case of the professional boxer, an electroencephalogram (EEG) is also required. When death occurs from an acute head injury, it is nearly always caused by intracranial bleeding: subdural hemorrhage into one of the middle cranial fossae is the most common postmortem finding. These hemorrhages are thought to be caused by prolonged battering resulting in bleeding from the dural emissary veins. Serious eye injuries are rare but cases of retinal detachment, paralytic diplopia, and optic atrophy have all been reported.