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Flashcards in Brain Blood Supply Deck (34):

Vascular components of brain and brainstem

Internal carotid arteries, maxillary artery and basil are artery

Vertebral to brainstem


Circle of Willis

Surrounds pituitary

Provide all blood to the brain

Rostral, middle and caudal cerebral arteries from here


Internal carotid

Main supply in dog and horse

Rudimentary in car and cow, have rete mirabile system, room smaller vasculature


Rete mirabile

Vascular redundancy or collateral paths of blood to the brain

Can compensate for carotid blockage and avoid brain damage



Circle of Willis makeup

Basilar supplies majority of blood to the brain

Cerebral hemispheres supplied by 3 cerebral arteries

Cerebellum by 2 pairs of arteries

Left and right internal carotids feed the circle



In dogs maxillary artery is a significant contribution to the internal carotid

Dogs can have rudimentary rete

Pharyngeal arteries can also anastomose along with external ophthalmic and ethmoidal arteries

Vertebrobasilar system supplies blood to cerebral hemispheres via caudal cerebral arteries


Cat/small ruminants

Internal carotid A regress after birth

Blood supply to circle via numerous small dorsal branches of maxillary arteries

Rostral epidural rete mirabile which coalesce into intracranial carotid arteries supplying cerebral arteries

Vertebrobasilar arteries though present have reduced contribution to the brain

Blood flow directed caudal in basilar artery so cerebral hemispheres sourced room intracranial internal carotid



Internal carotid regress and replaced by maxillary arteries which supply rete mirabile and intracranial off of here

Caudal rete connects to rostral

Vertebral arteries and spinal branches contribute to caudal rete which connects to rostral rete so the vertebrobasilar system contributes to whole Brain



After exiting heart supply complex anastomoses

Almost all blood to circle of Willis supplied by epidural retia rather than carotid branches


Dog anastomoses

5 can contribute to brain supply so can avoid defects when carotid and vertebral arteries are blocked

Occipital and vertebral

Ascending pharyngeal and internal carotid

Intracranial and maxillary

Maxillary and internal carotid

Ophthalmic and carotid


Venous drainage

Internal and external jugular veins and vertebrobasilar veins


Internal jugular vein

Begins as sigmoid and ventral petrodollars sinuses which join the vertebral vein


Maxillary vein

Branch of external jugular

Retroarticular vein connection from the temporal Dural sinus


Vertebral veins

Bilateral, receive blood from Brain through sigmoid sinus and vein of the hypoglossal canal


Internal vertebral venous plexus

Basilar sinuses

Numerous anastomoses connect to the external vertebral plexus that surrounds cervical and cranial thoracic vertebrae


Emissary vein

Join with ophthalmic, pterygoid and palatine plexus

Also connect cavernous sinuses and maxillary vein


Intracranial veins

Directly drain the brain

Plain veins draining parts of the surface of the brain

Dural veins/ sinuses within subarachnoid and intradural spaces


Dural veins and sinuses

Receive the blood draining into the cerebral veins


Intracranial vein drainage

Cortical and central veins which have different draining

Cortical veins turn to dorsal and ventral cerebral which drain into dorsal Sagittal and petrosal sinuses

Central veins drain into great cerebral


Cortical veins

Dorsal and ventral cerebral veins which drain the cortex and nearly the whole cerebrum


Central veins

Drain the great cerebral vein, corpus callosal, basal , internal cerebral and thalamostriate veins


Brainstem veins

Medullary and pontine veins


Dog cavernous sinuses

Significant portion of blood from Dural sinuses also drains into neural canal of the vertebral column

Vertebral plexus receive large volume of the blood draining from the CNS


Species variation in venous drainage

Aquatic mammals have an increased dependence on epidural venous drainage of blood from the brain


Brain cooling and pulse dampening

Sensitive to temperature changes

Veins regulate temperature and cool arteries to prevent dysfunction

Lack of carotid rete precludes cooling

Carotid rete and epidural retia have pulse dampening effect


Extracranial veins

Jugular veins and vertebral veins

Internal and external vertebral venous plexus
Internal within neural canal, external around vertebral column


Spinal cord arterial supply

Cervical- vertebral arteries

Thoracic spinal cord- dorsal and supreme intercostal arteries

Lumbar spinal cord- lumbar dorsal segmental arteries


Pia network

Anastomoses between dorsal and ventral root arteries and ventral spinal artery

White matter supplied by Pial network, and gray matter by ventral spinal artery


Spinal cord venous drainage

1. Central veins, radial veins and coronal plexus (pial)

2. Ventral median and dorsal spinal veins

3. Radicular and medullary veins

4. Internal and external vertebral plexus

5. Intervertebral veins


CNS components

Blood, neural tissue and cerebrospinal fluid

Increase in volume increases pressure


Internal and external carotid brain supply

Internal to external

Horse, dog, cat then cow


3 main paths of blood to the brain

Internal And external carotid and vertebral artery


3 main blood drainage from the Brain

Internal and external jugular and vertebrobasilar/ epidural veins

Internal and external jugs in soft tissue so can have pressure increase

Collateral epidural venous system protected inside neural canal


Blood supply to spinal cord review

Begins in aorta and moves up segmental arteries which give off spinal Ramus which enters neural canal and divides into dorsal and ventral root arteries

Ventral medullary artery enters the median ventral spinal artery and dorsal medullary artery enters one of the dorsal spinal arteries