Blood Supply to Brain and Spinal Cord Flashcards
How is the brain supplied with blood?
By anatomoses between the internal carotid arteries and the vertebral arteries
Where do the arteries supplying the brain anastomose?
At the circulus arteriosus / Circle of Willis
What completes the circulation around the circle of Willis?
The anterior and posterior communicating arteries
Where do the cerebellar arteries given off from the circle of Willis run into?
The subarachnoid space
What is the advantage of the anastomoses provided by the circle of Willis?
It provides enough anastomoses so that in theory, any blockage of one of the arteries will allow sufficient blood supply to reach and perfuse the region
What route does the internal carotid artery take in the skull?
It runs in the carotid canal of the petrous temporal bone, passing through the cavernous sinus, to enter the middle cranial fossa
What does the internal jugular vein divide into?
Anterior, , middle, and posterior communicating arteries
What does the posterior communicating artery join with?
The posterior cerebral artery
What course do the vertebral arteries take?
They ascend through the transverse foramen in the upper 6 cervical vertebrae, and enter the posterior cranial fossa via the foramen magnum
What is formed when the two vertebral arteries unite?
The basilar artery
Where do the vertebral arteries unite to form the basilar artery?
At the lower border of the pons
What happens to the basilar artery?
It bifurcates to form the posterior cerebral artery
Label this diagram showing the arteries of the Circle of Willis
A - Anterior communicating artery B - Anterior cerebral artery C - Opthlamic artery D - Anterior choroidal artery E - Posterior cerebral artery F - Superior cerebellar artery G - Basilar artery H - Anterior inferior cerebellar artery I - Vertebral artery J - Posterior inferior cerebellar artery K - Anterior spinal artery L - Pontine arteries M - Posterior communicating arteries N - Middle cerebral artery O - Internal cartoid artery
What arteries provide the cerebral cortical supply?
Anterior cerebral arteries Middle cerebreal arteries Posterior cerebral arteries
What do the anterior cerebral arteries supply?
The medial surfaces of the frontal and parietal lobes, continuing to the parieto-occipital sulcus Leg area of motor and somatosensory cortex
What do the middle cerebral arteries supply?
The lateral surface of the cerebral cortex Most of the dorsilateral surface The motor and sensory area of the central sulcus, apart from the leg areas Speech and language areas
How does the middle cerebral artery differ from the anterior?
It is larger
What do the posterior cerebral arteries supply?
Inferior surface of the brain Occipital lobes
Where does the posterior communicating arteriesarise from?
They are the terminal branches of the basilar arteries
Where do the pontine arteries arise from?
The basilar artery
What do the pontine arteries supply?
The pons and adjacent regions of the brani
What arteries supply the cerebellum?
Superior cerebellar artery Anterior inferior cerebellar artery Posterior inferior cerebellar artery
What does the superior cerebellar artery arise from?
It is the terminal branch of the basilar artery
Where does the anterior inferior cerebellar artery arise from?
The basilar artery
Where does the posterior inferior cerebellar artery arise from?
Branch of vertebral arteries
What provides the venous drainage of the brain?
Cerebral veins and venous sinuses, all eventually draining into the internal jugular vein
What categories can the cerebral veins be divided into?
External and internal
What are the external cerebral veins also known as?
Bridging
Where are the external cerebral veins found?
In the subarachnoid space
Broadly, what do the internal cerebral veins drain?
Deeper structures
Where do the internal cerebral veins emerge from?
The transverse fissure
Where are the dural venous sinuses found?
Within the dura mater layers
What must the external cerebral veins do to enable them to drain into the venous sinuses?
Cross the subdural space
What is the clinical relevance of the bridging veins crossing the subdural space to drain into the venous sinuses?
It has an accompanying risk of subdural haemorrhage following any head trauma
Label this diagram illustrating the venous sinuses involved with venous drainage of the brain
A - Superior sagittal sinus B - Inferior sagittal sinus C - Straight sinus D - Transverse sinus E - Confluence of sinus F - Superior and inferior petrosal sinuses G - Occipital sinus H - Sigmoid sinus I - Cavernous sinus J - Beginning of superior saggital sinus
Label this diagram illustrating the veins and plexuses involved in draining the brain
A - Great cerebral vein B - Internal vertebral venous plexus C - Basilar plexus D - Facial vein E - Deep facial veins F - Maxillary veins G - Pterygoid plexus H - Inferior opthlamic vein I - Superior opthlamic vein J - Supra-orbital vein K - Superior cerebral veins
What arteries descend through the spinal cord?
Anterior spinal artery Paired posteiror spinal arteries
What do the anterior and posterior spinal arteries descend the spinal cord within?
The pia mater
What are the anterior and posterior spinal arteries reinforced by during their descend through the spinal cord?
Multiple radicular arteries
What do the posterior spinal arteries supply?
The dorsal columns
What do the anterior spinal arteries supply?
The rest of the cord, other than the dorsal columns
What radicular artery is found in the lower thoracic and upper lumbar regions?
The arteria radicularis magnus (of Adamkiewicz)
What may occulsion of the arteria radicularis magnus cause?
Neural dysfunction
