Neurology - Anatomy and Physiology (2) Flashcards
1
Q
Cerebral arteries—cortical distribution (459)
- Anterior cerebral artery
- Middle cerebral artery
- Posterior cerebral artery
A
- Anterior cerebral artery
- Supplies anteromedial surface
- Middle cerebral artery
- Supplies lateral surface
- Posterior cerebral artery
- Supplies posterior and inferior surfaces
2
Q
Watershed zones
A
- Between anterior cerebral/middle cerebral, posterior cerebral/middle cerebral arteries.
- Damage in severe hypotension –> upper leg/upper arm weakness, defects in higher-order visual processing.
3
Q
Regulation of cerebral perfusion (459)
A
- Brain perfusion relies on tight autoregulation.
- Cerebral perfusion is primarily driven by Pco2
- Po2 also modulates perfusion in severe hypoxia
- Therapeutic hyperventilation (decreased Pco2) helps decrease intracranial pressure in cases of acute cerebral edema (stroke, trauma) via decreased cerebral perfusion by vasoconstriction.
4
Q
Effects of strokes:
Middle Cerebral Artery (MCA)
- Type of artery / circulation
- Area of lesion
- Symptoms
A
- Type of artery / circulation
- Anterior circulation
- Area of lesion
- (1) Motor cortex—upper limb and face.
- (2) Sensory cortex—upper limb and face.
- (3) Temporal lobe (Wernicke area); frontal lobe (Broca area).
- Symptoms
- (1) Contralateral paralysis
- Upper limb and face.
- (2) Contralateral loss of sensation
- Upper and lower limbs, and face.
- (3) Aphasia if in dominant (usuallyleft) hemisphere.
- Hemineglect if lesion affects nondominant (usually right) side.
- (1) Contralateral paralysis
5
Q
Effects of strokes:
Anterior Cerebral Artery (ACA)
- Type of artery / circulation
- Area of lesion
- Symptoms
A
- Type of artery / circulation
- Anterior circulation
- Area of lesion
- (1) Motor cortex—lower limb.
- (2) Sensory cortex—lower limb.
- Symptoms
- (1) Contralateral paralysis—lower limb.
- (2) Contralateral loss of sensation—lower limb.
6
Q
Effects of strokes:
Lenticulo-striate artery
- Type of artery / circulation
- Area of lesion
- Symptoms
- Notes
A
- Type of artery / circulation
- Anterior circulation
- Area of lesion
- Striatum, internal capsule.
- Symptoms
- Contralateral hemiparesis / hemiplegia.
- Notes
- Common location of lacunar infarcts, 2° to unmanaged hypertension.
7
Q
Effects of strokes:
Anterior Spinal Artery (ASA)
- Type of artery / circulation
- Area of lesion
- Symptoms
- Notes
A
- Type of artery / circulation
- Posterior circulation
- Area of lesion
- (1) Lateral corticospinal tract.
- (2) Medial lemniscus.
- (3) Caudal medulla—hypoglossal nerve.
- Symptoms
- (1) Contralateral hemiparesis—upper and lower limbs.
- (2) Decreased contralateral proprioception.
- (3) Ipsilateral hypoglossal dysfunction (tongue deviates ipsilaterally).
- Notes
- Stroke commonly bilateral.
-
Medial medullary syndrome
- Caused by infarct of paramedian branches of ASA and vertebral arteries.
8
Q
Effects of strokes:
Posterior Inferior Cerebellar Artery (PICA)
- Type of artery / circulation
- Area of lesion
- Symptoms
- Notes
A
- Type of artery / circulation
- Posterior circulation
- Area of lesion
- Lateral medulla—vestibular nuclei, lateral spinothalamic tract, spinal trigeminal nucleus, nucleus ambiguus, sympathetic fibers, inferior cerebellar peduncle.
- Symptoms
- Vomiting, vertigo, nystagmus
- Decreased pain and temperature sensation from ipsilateral face and contralateral body
- Dysphagia, hoarseness, decreased gag reflex
- Ipsilateral Horner syndrome
- Ataxia, dysmetria.
- Notes
- Lateral medullary (Wallenberg) syndrome.
- Nucleus ambiguus effects are specific to PICA lesions.
- “Don’t pick a (PICA) horse (hoarseness) that can’t eat (dysphagia).”
9
Q
Effects of strokes:
Anterior Inferior Cerebellar Artery (AICA)
- Type of artery / circulation
- Area of lesion
- Symptoms
- Notes
A
- Type of artery / circulation
- Posterior circulation
- Area of lesion
- (1) Lateral pons—cranial nerve nuclei, vestibular nuclei, facial nucleus, spinal trigeminal nucleus, cochlear nuclei, sympathetic fibers.
- (2) Middle and inferior cerebellar peduncles.
- Symptoms
- (1) Vomiting, vertigo, nystagmus.
- Paralysis of face, decreased lacrimation, salivation, decreased taste from anterior 2⁄3 of tongue, decreased corneal reflex.
- Face—decreased pain and temperature sensation.
- Ipsilateral decreased hearing.
- Ipsilateral Horner syndrome.
- (2) Ataxia, dysmetria.
- (1) Vomiting, vertigo, nystagmus.
- Notes
-
Lateral pontine syndrome.
- Facial nucleus effects are specific to AICA lesions.
- “Facial droop means AICA’s pooped.”
-
Lateral pontine syndrome.
10
Q
Effects of strokes:
Posterior Cerebral Artery (PCA)
- Type of artery / circulation
- Area of lesion
- Symptoms
A
- Type of artery / circulation
- Posterior circulation
- Area of lesion
- Occipital cortex, visual cortex.
- Symptoms
- Contralateral hemianopia with macular sparing.
11
Q
Effects of strokes: Basilar artery (BA)
- Type of artery / circulation
- Area of lesion
- Symptoms
- Notes
A
- Type of artery / circulation
- Posterior circulation
- Area of lesion
- Pons, medulla, lower midbrain, corticospinal and corticobulbar tracts, ocular cranial nerve nuclei, paramedian pontine reticular formation.
- Symptoms
- Preserved consciousness and blinking, quadriplegia, loss of voluntary facial, mouth, and tongue movements.
- Notes
- “Locked-in syndrome.”
12
Q
Effects of strokes:
Anterior Communicationg Artery (ACom)
- Type of artery / circulation
- Area of lesion
- Symptoms
- Notes
A
- Type of artery / circulation
- Communicating artery
- Area of lesion
- Most common lesion is aneurysm.
- Can lead to stroke.
- Saccular (berry) aneurysm can impinge cranial nerves.
- Symptoms
- Visual field defects.
- Notes
- Lesions are typically aneurysms, not strokes.
13
Q
Effects of strokes:
Posterior Communicating Artery (PCom)
- Type of artery / circulation
- Area of lesion
- Symptoms
- Notes
A
- Type of artery / circulation
- Communicating artery
- Area of lesion
- Common site of saccular aneurysm.
- Symptoms
- CN III palsy—eye is “down and out” with ptosis and pupil dilation.
- Notes
- Lesions are typically aneurysms, not strokes.
14
Q
Aneurysms
- Definition
- Berry aneurysm
- Location
- Findings
- Associated with…
- Other risk factors
- Charcot-Bouchard microaneurysm
A
- Definition
- In general, an abnormal dilation of artery due to weakening of vessel wall.
-
Berry aneurysm
- Location
- Occurs at the bifurcations in the circle of Willis [A].
- Most common site is junction of the anterior communicating artery and anterior cerebral artery.
- Findings
- Rupture (most common complication) leads to subarachnoid hemorrhage (“worst headache of life”) or hemorrhagic stroke.
- Can also cause bitemporal hemianopia via compression of optic chiasm.
- Associated with…
- ADPKD, Ehlers-Danlos syndrome, and Marfan syndrome.
- Other risk factors
- Advanced age, hypertension, smoking, race (increased risk in blacks).
- Location
-
Charcot-Bouchard microaneurysm
- Associated with chronic hypertension
- Affects small vessels (e.g., in basal ganglia, thalamus).
15
Q
Central post-stroke pain syndrome
A
- Neuropathic pain due to thalamic lesions.
- Initial sensation of numbness and tingling followed in weeks to months by allodynia (ordinarily painless stimuli cause pain) and dysaesthesia.
- Occurs in 10% of stroke patients.