Lecture 2 Flashcards
What are the 2 systems of arteries that are connected by communicating arteries to form the circle of Willis?
The Vertebrobasilar (posterior) system and the Carotid (anterior) system.
Which arterial system provides the anterior and middle cerebral arteries?
The carotid system
Which areas of the brain does the posterior cerebral artery supply?
Supplies part of the occipital lobes and the visual cortex.
Which cerebral artery supplies Broca’s and Wernicke’s areas? What are these areas responsible for?
Middle cerebral artery. Broca’s –> language production. Wernicke’s –> comprehension and understanding of written/spoken language.
Which cerebral artery supplies the medial part of the cerebral hemispeheres?
The anterior cerebral artery.
What are the lenticulostriate arteries and which 2 structures do they supply?
They are small branches from the anterior and middle cerebral arteries and they supply the basal ganglia and the internal capsule.
Which arterial system supplied the cerebellum?
The verterbrobasilar system.
What are the 3 main arteries supplying the cerebellum and where abouts in the cerebellum do they supply?
Superior cerebellar artery (SCA)
- Anterior inferior cerebellar artery (AICA)
- Posterior inferior cerebellar artery (PICA)
What is Wallenberg’s syndrome?
Also called PICA syndrome. Caused by ischemia to the lateral medulla due to blockage of the posterior inferior cerebellar artery (PICA). Symptoms are related to lateral medulla function (problems with the sensory aspects of the trigeminal nerve and paralysis of speech and swallowing) and balance problems related to the cerebellum.
What do the meningeal vessels supply?
The meninges and skull bones.
What is the name of the largest meningeal artery and why is it prone to injury?
The middle meningeal artery. It enters the skull through the foramen spinosum and passes deep to pterion where the cranium is thin and is therefore a common site of fracture –> can lead to extradural haemorrhage.
What type of haemorrhage can be seen in this CT scan?
Extra-dural haemarrhage caused by injury to the MMA
What are the dural venous sinuses and what is their function?
venous channels found between the endosteal and meningeal layers of dura mater in the brain. They receive blood from internal and external veins of the brain, receive CSF from the subarachnoid space via arachnoid granulations and mainly empty into the internal jugular vein.
Name the dural sinuses and the describe the flow of blood between them
Which cranial nerves pass through the lateral wall of each cavernous sinus?
Cranial nerves III, IV and VI
What would happen if the dural venous sinuses were a sight of major thrombosis?
Reabsorption of CSF would be blocked leading to raised ICP in the sub-arachnoid space.
What is the main cause of a subdural hematoma?
small veins run into the dural venous sinuses from brain tissue, these get stretched as we age or by trauma/disease. Normally tear where they enter the dural sinuses between the dura and arachnoid –> blood collects between the dura and arachnoid.
What are the CSF cisterns?
dilated areas of the cranial subarachnoid space containing CSF
Describe the route of CSF production and movement
CSF is produced by the choroid plexus à floor of lateral ventricles à through foramen of Monroe à roof of 3rd ventricle à aqueduct of sylvuis à posterior roof of 4th ventricle à foramen of Magendie à foramen of Luschka
What are the 3 main causes of hydrocephalus and what is the disease progression?
may be caused by an overproduction of CSF, a failure to reabsorb it or by a blockage of the ventricles.Causes expansion of the volume of the ventricles which compresses the brain tissue, raised ICP, cerebral oedema or herniation.
How can you treat hydrocephalus?
Treated with cerebral shunt surgery to reduce the accumulation of CSF to another part of the body.
What would be visible upon examination of a patient with nerve damage to CN III (oculomotor)?
Ptosis (weak levator palpebrae superioris), lateral squint (unopposed superior oblique and lateral rectus), pupillary dilation (unopposed sympathetic activity and loss of accommodation.
