Blood Supply to the Brain Flashcards
Brains blood supply components
Two Internal Carotid Arteries
Two Vertebral Arteries
Form the three major branches:
- Anterior Cerebral Artery
- Middle Cerebral Artery
- Posterior Cerebral Artery
All components of the circle of Willis.
What portion of the brain does the ACA Supply?
Anterior Frontal Lobe
Medial Surface of the Frontal Lobes and the Parietal Lobes
What are possible deficits caused by ACA involvement?
- Contralateral LE motor and sensory involvement
- Apraxia & Aphasia (Broca’s) (“BEN has Aphasia”)
- Loss of behavioral control; impulsivity
- Mental/personality/emotional changes
- Neglect, preservation
- Loss of bowel and bladder control
What portions of the brain does the MCA Supply?
Outer Cerebrum
- Basal Ganglia; Putamen, Globus Pallidus
- Posterior and Anterior Internal Capsule
- Lentiform Nucleus
What are possible deficits caused by MCA involvement? Differences found in Left and Right Hemisphere Damage
Left Hemisphere Damage:
- Contralateral weakness and sensory loss to the face and UE
- (Wernicke’s; Fluent; Receptive Aphasia)
- Homonymous Hemianopsia; is a visual field defect involving either the two right or the two left halves of the visual fields of both eyes.
- Limb-Kinetic Apraxia
Right hemisphere damage:
- Flat Affect
- impaired spatial regulation, body schema
- Anosognosia in the [non-dominant hemisphere]; Anosognosia, also called “lack of insight,” is a symptom of severe mental illness experienced by some that impairs a person’s ability to understand and perceive his or her illness.; Neglect
What portions of the brain does the PCA Supply?
Portions of the midbrain (mesencephalon)
Subthalamic Nucleus, Basal Nucleus
Thalamus
Inferior Temporal Lobe
Occipital and occipitoparietal cortices
What are possible deficits caused by PCA involvement?
Movement Deficits:
Visual Deficits:
Additional Deficits:
Contralateral Deficits:
Movement Deficits:
- Ataxia, athetosis or choreiform movements
- Movement quality impairments
Visual Deficits:
- Visual agnosia, Prosopagnosia; Facial Blindness
- Homonymous Hemianopsia
- Cortical Blindness from bilateral involvement
- Alexia and Dyslexia
- Topographical Disorientation
Additional Deficits:
- Memory Impairment; (inferior temporal lobe)
- Thalamic Pain Syndrome
Contralateral Deficits:
- Contralateral pain and temperature loss
- Contralateral hemiplegia
What portions of the brain does the Vertebral-Basilar Artery supply?
Lateral aspects of the pons and the midbrain
Superior Surface of the cerebellum.
What branches supply the Cerebellum
Branches from the basilar artery:
- Posterior inferior cerebellar artery (PICA)
- Anterior inferior cerebellar artery (AICA)
- Superior Cerebellar Artery
What branches supply the Medulla
Posterior Inferior Cerebellar Arteries (PICA)
and
small branches from the vertebral arteries
What branches supply the Pons
Branches of the basilar artery
What branches supply the Midbrain and Thalamus
Posterior Cerebral Arteries
What branches supply the Occipital Cortex
Posterior Cerebral Arteries
What are deficits caused by involvement to the Vertebral-Basilar Artery?
- Loss of Consciousness: LOC
- Comatose or Vegetative States
- Locked in Syndrome
- Hemiplegia or tetraplegia
- Vertigo, Nystagmus, Ataxia
- Dysphagia & Dysarthria; inability to speak
Bilateral occlusion of the ACA Deficits
- Paraplegia; paralysis of the legs and lower body
- incontinence
- Abulic Aphasia; [Definition: also known as apathy, psychic akinesia, and athymia, refers to a lack of will, drive, or initiative for action, speech and thought]
- Frontal lobe symptoms: personality changes, potential Akinetic Mutism
[Definition: Akinetic mutism (AM) is a rare neurological disorder characterized by the presence of an intact level of consciousness and sensorimotor capacity, but with a simultaneous decrease in goal-directed behavior and emotions. Patients are in a wakeful state of profound apathy, seemingly indifferent to pain, thirst, or hunger.]
Bilateral occlusion of the MCA Deficits
Contralateral hemiplegia and sensory impairments
- Dominant hemisphere involvement: Global, Wernicke’s and Broca’s aphasia
What are the two most significant impairments caused by the PCA
- Thalamic Pain Syndrome
- Cortical Blindness
What is thalamic pain syndrome?
Abdormal sensations of pain, temperature, touch, proprioception
- Can become debilitating
What is Cortical Blindness?
loss of vision due to damage of the visual portion of the occipital cortex
- pupil can still dilate and constrict in response to light. (Intact pupillary light reflex)
Severe impairments caused by the Vertebral-Basilar Artery
- Locked in Syndrome
- Coma and Vegetative States
- Wallenberg Syndrome
What is Wallenberg Syndrome: Secondary to Lateral Medullary Infarct
Ispilateral
- Facial Pain and Temperature Impairment
- Cerebellar Ataxia, Vertigo, Nystagmus
- Dysphagia (CN 9 and 10)
- Horner’s Syndrome (Descending Sympathetic Tracts)
Contralateral
- Pain and Temperature Impairment of the Body
What is Horner’s Syndrome?
Ptosis; Dropping Upper Eyelid
Miosis; Decreased Pupillary Size
Anhidrosis; Decreased Sweating on Ipsilateral Face and Neck
What is Locked- In Syndrome
As a result of a Complete Basilar Stroke
- Tetraplegia and often Bilateral Cranial Nerve Palsy (with **sparing of upward gaze, blinking **)
- COMA if (RAS: Reticular Activating System Disrupted)
- Cognition is Spared
Medial Medullary Syndrome
Ipsilateral
- Paralysis of 1/2 of tongue (CN 12)
(Deviation towards the paralyzed (weak) side on protrusion)
Contralateral
- Hemiparesis (UE and LE: due to Corticospinal Tract Disruption)
- Impaired Tactile and Proprioceptive Sense (Medial Lemniscus)
