Vasculature Flashcards
Posterior circulation (what arteries, how do they travel, where do they enter cranial cavity)
- vertebral arteries arise from subclavian arteries
- ascend through transverse foramina of cervical vertebra
- enter cranial cavity via foramen magnum
Anterior circulation (what arteries, how do they travel, where do they enter cranial cavity)
- internal carotid arteries are terminal branch of common carotid arteries
- ascend through neck to base of skull
- enter cranial cavity via carotid canal
What do the vertebral arteries supply blood to?
spinal cord, brainstem, cerebellum, occipital lobe, and portions of the temporal lobe and diencephalon
Where do vertebral arteries fuse/what is this new artery called?
fuse at pontomedullary junction to form basilar artery
Anterior/posterior spinal arteries
arise from, how many, location/blood supply
arise from vertebral arteries
1 anterior, 2 posterior
Anterior: travels midline spinal cord, supplies blood to anterior 2/3 of spinal cord
Posterior: travel posterior to dorsal horn (bilaterally), supply blood to posterior 1/3 of spinal cord.
What reinforce the anterior/posterior spinal arteries? Where do they come from?
- radicular arteries reinforce
- branches of posterior intercostal arteries
Great radicular artery
- at T12
- provides entire arterial supply for lumbosacral spinal cord
List flow of blood caudal to rostral from vertebral artery (7)
- vertebral artery
- posterior inferior cerebellar artery (PICA) branches off
- fuse to form basilar artery
- anterior inferior cerebellar artery (AICA) branches off of caudal basilar artery
- Internal auditory/labyrinthine artery branches off of basilar artery or AICA
- many pontine arteries branch off
- superior cerebellar artery branches off of rostral basilar artery
- basilar artery bifurcates to form two posterior cerebral arteries
Internal auditory/labyrinthine artery
supplies inner ear
occlusion can lead to vertigo and ipsilateral deafness
blood supply of caudal medulla
-branches of anterior spinal artery, vertebral artery, PICA and posterior spinal artery
blood supply of rostral medulla
branches of anterior spinal artery, vertebral artery, PICA
blood supply to pons
- mainly by branches of basilar artery
- caudal pons also by anterior AICA (dorsal lateral pons)
- rostal pons also by superior cerebellar artery (dorsal lateral pons)
blood supply to midbrain
- mainly by posterior cerebral arteries
- dorsal midbrain also by superior cerebellar artery
blood supply to cerebrum
- posterior cerebral artery supplies occipital lobe and medial/inferior surface of temporal lobe
- middle cerebral artery supplies most of homunculus, internal capsule, deep grey matter (BG)
- anterior cerebral artery supplies frontal lobe (only leg of honumculus), also caudate and putamen
Lesion to posterior spinal cord blood supply will cause
vibration and position sense loss in neck and below
lesion to anterior spinal cord blood supply will cause
pain, temperature, motor sense loss in neck and below
Wallenberg’s syndrome
- lateral medullary syndrome
- caused by ischemia of verebral artery and/or PICA
- affects ipsilateral: inferior cerebellar peduncle, vestibular nuclei trigeminal nucleus, descending sympathetic fibers, nucleus solitarius
- affects contralateral: spinothalamic tract
- other: nucleus ambiguus
Locked in syndrome
- bilateral ventral pons ischemia (secondary to insufficent blood supply through basilar artery)
- only capable of eye movements
- consciousness is spared
Components of Circle of Willis (5)
- anterior communicating artery
- anterior cerebral arteries (from internal carotid)
- internal carotid arteries
- posterior communicating arteries (from internal carotid)
- posterior cerebral arteries
lenticulostriate arteries
small lateral branches of middle cerebral arteries which supply blood to internal capsule, deep gray matter
Menignes organization
- dura (outside)
- arachnoid (middle)
- pia (internal)
layers of dura mater
- external periosteal layer: adheres to internal surface of skull, formed by periosteum
- internal meningeal layer: dense fiberous CT
Two largest dural reflections:
- Falx cerebri: largest, invaginates along longitudinal fissure between two cerebral hemispheres
- Tentorium cerebelli; tent over cerebellum (between cerebellum and occiptial/temporal lobes
Flow of blood from capillaries:
cerebral arteries -> capillaries -> cerebral veins -> venous sinuses -> internal jugular vein
Epidural space
-potential space between skull and outer layer of dura
epidural hemorrhage/hematoma
- from trauma/skull fracture
- tearing of meningeal artery
- bleeding into epidural space with no space to expand
middle meningeal artery and vein
enclosed by periosteal dura
Subdural space
-potential space between dura and arachnoid mater
subdural hemhorrhage/hematoma
- from rapid acceleration/deceleration
- pulls brain away from skull, tears cerebral veins as they enter dural sinus
Subarachnoid space
-true space between arachnoid and pia mater
Subarachniod hemhorrhage/hematoma
- typically arterial hemhorrhage
- leads to blood in CSF
- secondary to aneurysm or trauma
Communication between ventricles
(Two) lateral ventricles communicate via
Interventricular foramen/foramen of Monroe to
(one) 3rd ventricle which communicates via
Cerebral aqueduct/Aqueduct of Sylvius to
(one) 4th Ventricle
Flow of CSF
- made in choroid plexus
- leaves ventricles by exiting 4th ventricle
- via Foramen of Magendie or pair of Foramen of Luschka
- to subarachnoid space
- to dural venous sinuses via arachnoid granulations
