Exam 2 week 6 ppt 7 & 8 Blood Supply and Vascular disorders of brainstem structures Flashcards
name the arteries in the picture of an overall veiw the the vascular supply to the brainstem
- Anterior spinal artery
- Posterior spinal artery
- Vertebral Artery
- Posterior inferior cerebellar artery
- Basilar artery
- Anterior inferior cerebellar artery
- Circumferential artery
- Superior cerebellar artery
- Posterior cerebral artery
Explain the vertebrobasilar system: purpose and path
The brainstem is supplied with blood via the Vertebrobasilar system.
•Vertebrobasilar system
- –Vertebral arteries arise from subclavian arteries
- –Rise thru transverse foramina of cervical vertebrae to enter skull thru foramen magnum
- –Run along ventral brainstem to form single basilar artery at caudal pons
The brainstem is supplied with blood via the Vertebrobasilar system. Vertebral arteries arise from subclavian arteries and Rise thru transverse foramina of cervical vertebrae to enter skull thru foramen magnum. The vertebral arteries then run along ventral medulla to form single basilar artery at caudal pons
Anterior and posterior spinal arteries
arise from what?
anterior spinal arteriy supplies what?
anterior spinal artery exits the cranium where and why?
Branches from the vertebral arteries
The anterior spinal artery supplies the medial medulla
The anterior spinal artery exits out through the foramen magnum to supply blood to the spinal cord
Posterioir inferior cerebellar arteries
abbreviation
where it arises
what does it supply?
PICAs
Paired branches off the vertebral artery
supplies blood to
- the cerebellum
- lateral medulla
Another name for Lateral Medullary Syndrome
Wallenberg’s Syndrome
Describe Lateral Medullary Syndrome
cause
structures damaged
- •Caused by occlusion of PICA or vertebral artery near PICA
- •Structures damaged include
- –Spinothalamic tract & Spinal nucleus & tract of V
- –CN VIII, IX, X & XI nuclei
- –Sympathetic descending tracts
Lateral Medullary Syndrome
Symptoms of damage to spino-thalamic tract & nucleus & tract of V
- Impaired pain and temperature sensibility over ipsilateral face and contralateral body
Symptoms of Lateral Medullary Syndrome (Wallenberg’s Syndrome) as the result of damage to the spino-thalamic tract & nucleus & tract of V are Impaired pain and temperature sensibility over ipsilateral face and contralateral body. Remember the spinothalamic tract has decussated but the trigeminal afferents have not
Lateral Medullary Syndrome
Symptoms of damage to vestibular nuclei
Symptoms of Lateral Medullary Syndrome (Wallenberg’s Syndrome) as the result of damage to the vestibular nuclei include
- §Nystagmus – involuntary movement of eyes
- §Diplopia – double vision
- §Vertigo – dizziness
- §Ipsiversive lateral pulsion (gait deviation of turning to the same side of the lesion)
Lateral Medullary Syndrome
Symptoms of damage to nuclei of CN IX & X (4)
Symptoms of Lateral Medullary Syndrome (Wallenberg’s Syndrome) as the result of damage to nuclei of CN IX & X include:
- Dysarthria
- dysphonia
- Diminished gag reflex
- Hiccups
Lateral Medullary Syndrome
Symptoms of damage to sympathetic tracts (3)
Symptoms of Lateral Medullary Syndrome (Wallenberg’s Syndrome) as the result of damage to sympathetic tracts incude:
- Horner’s syndrome which is
- Miosis (constricted pupil)
- Ptosis
- Anhydrosis (no sweating)
what is Horner’s syndrome? (with 3 symptoms)
damage to sympathetic tracts
Symptoms include:
- Miosis (constricted pupil)
- Ptosis
- Anhydrosis (no sweating)
Alternate name for Medial Medullary Syndrome
•alternating hypoglossal hemiplegia
Medial Medullary Syndrome:
Causes
Structures damaged (3)
- •Caused by occlusion of anterior spinal artery
- •Structures damaged
- –Medial lemniscus
- –medullary pyramid
- –Nucleus for CN XII
Medial Medullary syndrome (Also called alternating hypoglossal hemiplegia) occurs when there is occlusion of anterior spinal artery (illustrated as B in this picture)
Structures damaged include:
Medial lemniscus
medullary pyramid
Nucleus for CN XII
Medial Medullary Syndrome
Symptoms of damage to Medial lemniscus
–contralateral loss of discriminative touch and kinesthesia
Medial Medullary Syndrome
Symptoms of damage to pyramids
–contralateral spastic hemiparesis
Medial Medullary Syndrome
Symptoms of damage to CN XII Nucleus
Symptoms of Medial Medullary Syndrome as the result of damage to the CN XII Nucleus is atrophy of ipsilateral tongue and tongue deviation to the side of occulsion when protruded
List four branches of the basilar artery
- –Anterior inferior cerebellar arteries (AICAs)
- –Superior cerebellar arteries (SCAs)
- –Paramedian (pontine)branches
- –Posterior cerebral arteries (PCAs)
AICAs
Anterior inferior cerebellar arteries
Medial Inferior Pontine Syndrome:
cause
damages what? (5)
(an infarct of the Pons)
Caused by Occulsion of paramedian (pontine) artery branches of basilar artery
- –Damages CN VI nerve fibers –
- results in ipsilateral medial eye deviation due to paralysis of the lateral rectus
- –Corticospinal & corticobulbar tracts –
- spastic paralysis of contralateral face & body
- –Medial lemniscus –
- contralateral loss of discriminative touch and kinesthesia
- –Paramedian pontine reticular formation –
- ipsilateral horizontal gaze palsy
- –Pontine nuclei & pontocerebellar fibers –
- limb & gait ataxia
Lateral Superior Pontine Syndrome
cause
what it damages (4)
(infarct of the pons)
–Caused by superior cerebellar artery occlusion
- –Damage to Superior cerebellar peduncle –
- resulting in ipsilateral limb & gait ataxia & intention tremor
- –Spinothalamic & trigeminothalamic tracts –
- contralateral face & body loss of pain & temperature
- –Medial lemniscus –
- contralateral loss of discriminative touch and kinesthesia
- –Sympathetic tracts –
- ipsilateral Horner’s syndrome
Complete basilar syndrome
cause
produces
s/s
(infarct of the pons)
- caused by lack of lack of blood flow through both paramedian & circumferential (cerebellar) arteries
- produces Complete transection of pons
- –Signs & symptoms
- Coma & paralysis
- Pinpoint, unequal pupils
Locked In Syndrome
cause
structurea damaged
s/s
(Infart of the Pons)
- –May follow occlusion of the basilar artery but infarct confined to the ventral pons
- –spares ascending somatosensory pathways and ascending reticular activating system (ARAS)
- •Structures damaged include
- bilateral corticobulbar and
- corticospinal tracts
- bilateral corticobulbar and
- signs & symptoms
- •Fully conscious, but locked-in with near total paralysis
- •Inexpressible – only vertical eye movements remain
Locked-In Syndrome May follow occlusion of the basilar artery but infarct confined to the ventral pons and spares ascending somatosensory pathways (medial lemniscus & anterolateral systems) and ascending reticular activating system (ARAS). Locked in syndrome produces damaged bilateral corticobulbar and corticospinal tracts. But with intact ARAS the person is fully conscious, but locked-in with near total paralysis. Only inexpressive vertical eye movements remain. Imagine the horror of being able to perceive everything, be cognitively alert but be totally paralyzed and unable to communicate with the outside.
Weber’s Syndrome
cause
structure damaged
(infarct of the midbrain)
- –Caused by infarction of paramedian PCA branches in midbrain
- –Results in damage to:
- Cerebral peduncle (contains corticospinal & corticobulbar tracts)
- Oculomotor nerve (CN III)
Weber’s Syndrome (shown as A in this illustration) and also called superior alternating hemiplegia is Caused by infarction of paramedian PCA branches in midbrain. This condition results in damage to: cerebral peduncle containing the Corticospinal & corticobulbar tracts and the Oculomotor nerve
Benedikt’s Syndrome
cause
structures damaged (3)
(infarct of the midbrain)
- •Caused by occlusion of tegmental branch of the PCA
- •Structures damaged
- –Nucleus for CN III,
- red nucleus &
- cerebellothalamic tract
Benedikt’s Syndrome (B in this illustration) is Caused by occlusion of tegmental branch of the posterior cerebral artery. This results to
Damage in the Nucleus for CN III, red nucleus & cerebellothalamic tract
