Neurovascular Flashcards
Internal carotid
Branch of common carotid (at C4) Enters cranium via carotid canal of temporal bone Branches: Ophthalmic artery Posterior communicating artery Anterior cerebral artery Anterior choroidal artery Middle cerebral artery
Vertebral artery
Enters via foramen magnum Branches: Meningeal branches Anterior and posterior spinal arteries Posterior inferior cerebellar artery Forms basilar artery
Circle of Willis
Anterior cerebral arteries (branch of ICA)
Internal carotids
Posterior cerebral arteries (branch of BA)
“Connecting vessels”:
Anterior communicating (connects anterior cerebral arteries)
Posterior communicating (connects ICA with posterior cerebral)
Basilar arteries
Formed by two vertebral arteries over junction of medulla and pons Branches: Anterior inferior cerebellar artery Pontine arteries Superior cerebellar arteries Posterior cerebral arteries
Stroke syndromes
Anterior cerebral artery syndrome
Middle cerebral artery syndromes
Poster cerebral artery
Anterior inferior cerebellar artery (AICA)
Posterior inferior cerebellar artery (PICA)
Anterior cerebral artery syndrome
Rare due to collateral flow
Contralateral hemiparesis of lower limbs
Contralateral sensory loss of lower limbs
Anosmia
Middle cerebral artery syndromes
Contralateral weakness Contralateral sensory loss Contralateral hemineglect Contralateral homonymous hemianopia Global aphasia (receptive and expressive)
Basilar artery
Locked in syndrome
Anterior inferior cerebellar artery (AICA)
Lateral pontine syndrome: Marie-Fox Syndrome
Ipsilateral cerebellar ataxia (arm and leg)
Ipsilateral facial weakness
Ipsilateral hearing loss, vertigo and nystagmus
Posterior inferior cerebellar artery (PICA)
Lateral medullary syndrome (Wallenberg Syndrome)
Ipsilateral: Facial sensory loss Nystagmus Horner's syndrome Loss of gag reflex Ipsilateral ataxia with a tendency to fall to the ipsilateral side Contralateral: Pain and temperature sensory loss in the extremities
Dural venous sinuses
Lie between periosteal and meningeal dural layers
Drain into internal jugular vein
11 sinuses in total
Superior sagital sinus
Runs in falx cerebri
Collects from Superior cerebral veins
Connects with confluence of sinuses at internal occipital protuberance
Confluence of sinuses
Collection of:
Superior sagital sinus
Straight sinus
Occipital sinus
Drains into
R & L transverse sinuses
Inferior sagital sinus
Runs in falx cerebri in midline
Connects with great cerebral “vein of Galen” into: Straight sinus
Inferior sagital sinus
Runs in falx cerebri in midline
Connects with great cerebral “vein of Galen” into: Straight sinus
Great cerebral vein “Of Galen”
formed by joining of internal cerebral vein and basal vein of Rosenthal.
Joins with inferior sagital sinus to from straight sinus
Transverse sinus
Right and left
Drains from confluence of sinuses
Drains into sigmoid sinus
Cavernous sinus
Venous plexus on each side of sella turcica
CN3, CN4, CNV1, CNV2, CN6 and ICA travel though it.
Collects from inferior and superior ophthalmic veins
Drains into superior and inferior petrosal sinuses (onto transverse sinus and IJV)
Functions of CSF
Protection
Buoyancy
Chemical stability
Ventricles of the brain
Lateral ventricle
Third ventricle
Fourth ventricle
Lateral ventricle
R & L. Located within hemispheres of cerebrum.
“Horns” project into frontal, occipital and temporal lobes
Third ventricle
Connects to the lateral ventricles by the foramen of Munro
Situated between right and left thalamus
Fourth ventricle
Receives CSF from third ventricle via cerebral aqueduct
Lies within brainstem at junction of medulla and pons
Drains into:
Central spinal canal: bathes spinal cord
Subarachnoid cisterns: bathes brain between arachnoid and Pia
Production of CSF
Produces by choroid plexus, located in lining of ventricles.
Drainage of CSF
Occurs in subarachnoid space. Arachnoid granulations (small projections) into dura mater. Allowed fluid to drain into dural venous sinuses.
Cavernous Venous Sinus Thrombosis
Clot in Cavernous sinus
Most common cause: infection.
Typically spreads from extracranialu location: orbit, paranasal sinuses or “danger zone” of face. (Connection between ophthalmic veins and CS)
Sx: headache, unilateral periorbital oedema, proptosis, CN palsy (CN6 most common).
Can rapidly progress to meningitis
Neural tube normal embryology
Neural groove –> neural fold –> neural tube
Closes at approx day 28
4 divisions:
1. Forebrain (prosencephalon –> telencephalon: cerebrum & diencephalon: optic nerve/hypothalamus)
2. Midbrain (mesencephalon)
3. Hindbrain (rhombencephalon –> metencephalon: pons/cerebrum & myelencephalon: medulla oblongata)
4. Spinal cord
Neural tube defects
Failure of neural tube to close (day 28) Anencephaly Encephaloceles Hydranencephaly Iniencephaly Spina bifida (most common)
Anencephaly
Severe.
Failure for anterior most part of neural tube to fuse. Leading to lacking most parts of forebrain (cerebrum)
Infants die within hours/days of birth
Encephalocele
Protusions of cerebral material through skull into sac covered with membranes/skin
Hydranencephaly
Cerebral hemispheres are missing and filled with fluid
Spina bifida: types
Myelomeningocele
Meningocele
Spina bifida occulta
Spina bifida: Risk factors
Folate deficiency
Obesity
DM
Anti epileptics
Myelomeningocele
Most severe type
Spinal cord, meninges protrude from spinal column
If no skin covering: “open spina bifida”
Associated with Arnold-Chiari II malformation
Meningocele
Only meninges protruding through unformed spinal column
Spina bifida occulta
Most common. Least severe.
Spinal cord/surrounding tissue does not protrude.
Hair/dimple/birth mark at site of lesion.
