Neurovascular bundleV1V2Connected togetheras a structural unitSkinAponeurosisPeriosteum1234BoneOutertableInnertableDiploëAnterior cerebral arteryInternal carotidarteryDiploic veinSuperior sagittal sinusCavernous sinusOptic tractsDuraPeriostial layerMeningeal layerArachnoidSubarachnoid spacePiaEmissary vein: can spread infection fromthe scalp into the cranial cavityConnective tissue:contains majornerves and vesselsof the scalpFractureLoose connective tissue (danger area)• In scalping injuries, this is the layer in which separation occurs.• Infection can easily spread in this layer.• Blunt trauma can result in hemorrhage in this layer (blood can spread   forward into the face, resulting in “black eyes”).Rupture of the middle meningeal artery (branches) by fracture of the inner table of boneresults in extradural hematoma. Under pressure, the blood progressively separates dura from the bone.Aneurysm• Ruptured aneurysms of vessels of the cerebral arterial circle hemorrhage directly into the subarachnoid space and CSF.Tear to cerebral vein where it crosses dura to enter cranial venous sinus can result in subdural hematoma. The tearseparates a thin layer of meningeal dura from that which remains attached to the periosteal layer. As a result, thehematoma is covered by an inner limiting membrane derived from part of the meningeal dura.         ExtraduralhematomaSubdural hematomaVIIVIII1234