Vasculature of the CNS_ part 1 .pdf

18/09/24 Vasculature of the CNS: part 1 Learning objective: describe and differentiate bet ween the cerebral, cerebellar and brain stem arterial supply and trace their origin and anastomosis. Learning objective: describe cerebrospinal uid circulation and abnormalities that may interrupt the ow...

18/09/24 Vasculature of the CNS: part 1 Learning objective: describe and differentiate bet ween the cerebral, cerebellar and brain stem arterial supply and trace their origin and anastomosis. Learning objective: describe cerebrospinal uid circulation and abnormalities that may interrupt the ow of CSF. Learning objective: de ne and describe the dural venous sinuses and their venous ow pattern. Learning objective: describe how a haemorrhage or blockage could disrupt the ow of arterial, venous or CSF ow and the resulting implications. Arterial supply to the neck and head: 3 main arteries in this region: 1. External carotid. 2. Internal carotid. 3. Vertebral artery. Common carotid gives rise to the internal and external carotid. This bifurcates at C3-C5. The vertebral arteries come from the subclavian. ECA Marcillary Middle menigeal Middle meningeal artery and Pterion: The external carotid only generally supplies external features of the neck and head. It has a few different branches. 1. Maxillary artery. 2. Facial artery. 3. Super cial temporal artery. The maxillary artery gives rise to the MMA which is the largest of the meningeal branches and it passes into the cranial vault via the foramen spinosum. Pterion: This is an important feature of the skull; it is a suture point where 4 moves meet. Temporal. TSFP Sphenoid. Frontal. Parietal. Meningeal arteries: MMA is the largest of these arteries. Meningeal arteries all supply the dura mater. It passes very closely to the Pterion- the weakest point of the skull. Damage to this point of the skull can cause epidural haemorrhage. Arterial supply to the Brain: Cerebral arterial circle ( of Willis ). We divide the supply of these into anterior and posterior circulation. The anterior circulation comes from the ICA. There are right and left ICAs. The posterior circulation comes from the vertebral artery. The right and left vertebral arteries join to form the basilar artery. Anastomosis: this is a cross-connection bet ween adjacent channels, tubes or other parts of a net work. There are anastomoses bet ween the anterior and posterior circulation for the cerebral arterial circle. The Carotid System: The ICA passes through the carotid canal- a tunnel through the temporal bone. Initially passes over the cartilage of the foramen lacerum. Then passes through the cavernous sinus, pierce the dura matter to enter the sub-arachnoid space. Then gives rise to important branches, including the ophthalmic artery. Then the ICA terminates as the anterior and middle cerebral arteries. Anterior middletered Paige pass thenlacerum 7 passingthroughcarotid 7 externaliegion Carotid siphon is found after is leaves carotid canal and before it pierces the dura matter. The Vertebrobasilar System: Vertebral artery is a branch of the subclavian artery. Ascends through the neck via the transverse foramina of C1-C6. Vertebral arteries then pass through the foramen Magnum. Cerebral Arterial Circle: Anterior communicating Anterior cerebral A ICA middle cerebral A Esteem municating Posterior superior cerebellar cerebral pontine A AICA Basilar A DICA vertebral A Above the dotted line there is the anterior circulation from the carotid system and below the line the posterior from the vertebrobasilar system.