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Which of the following is NOT a predisposing factor for watershed areas to be prone to infarct?
Which of the following is NOT a predisposing factor for watershed areas to be prone to infarct?
The Anterior Cerebral Artery is abbreviated as ACA.
The Anterior Cerebral Artery is abbreviated as ACA.
True
What can sudden hypotension lead to in watershed areas of the brain?
What can sudden hypotension lead to in watershed areas of the brain?
Infarct
The condition characterized by low protein levels in the blood is called _____
The condition characterized by low protein levels in the blood is called _____
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Match the following brain arteries with their respective abbreviations:
Match the following brain arteries with their respective abbreviations:
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What condition results from bilateral involvement of upper motor neuron lesions?
What condition results from bilateral involvement of upper motor neuron lesions?
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Unilateral involvement of upper motor neuron lesions typically results in noticeable symptoms.
Unilateral involvement of upper motor neuron lesions typically results in noticeable symptoms.
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What is the primary effect of a supranuclear lesion on facial nerve function?
What is the primary effect of a supranuclear lesion on facial nerve function?
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The facial nerve's unilateral innervation is seen only in the _____ half of the face.
The facial nerve's unilateral innervation is seen only in the _____ half of the face.
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Match the arterial lesions to their primary affected region of the body:
Match the arterial lesions to their primary affected region of the body:
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What is a characteristic feature of upper limb weakness due to a UMN lesion?
What is a characteristic feature of upper limb weakness due to a UMN lesion?
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In UMN lesions, the facial nerve palsy affects both the upper and lower halves of the face equally.
In UMN lesions, the facial nerve palsy affects both the upper and lower halves of the face equally.
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What type of gait is characteristic of increased tone associated with UMN lesions?
What type of gait is characteristic of increased tone associated with UMN lesions?
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In a UMN lesion, the lower limb exhibits _____ due to loss of knee flexion.
In a UMN lesion, the lower limb exhibits _____ due to loss of knee flexion.
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Match the following reflexes with their corresponding root values:
Match the following reflexes with their corresponding root values:
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Which of the following symptoms is commonly associated with internal capsule lesions?
Which of the following symptoms is commonly associated with internal capsule lesions?
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Bilateral involvement is a characteristic feature of spinal cord lesions.
Bilateral involvement is a characteristic feature of spinal cord lesions.
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What is the primary function of the corticospinal tract?
What is the primary function of the corticospinal tract?
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The _____ delivers inhibitory impulses to lower centers in the body.
The _____ delivers inhibitory impulses to lower centers in the body.
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Match the following neurological tracts with their primary functions:
Match the following neurological tracts with their primary functions:
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What part of the brain contains the pyramidal cells of Betz?
What part of the brain contains the pyramidal cells of Betz?
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The anterior corticospinal tract primarily innervates skeletal muscles directly.
The anterior corticospinal tract primarily innervates skeletal muscles directly.
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Which structure is responsible for the decussation of the corticospinal tract?
Which structure is responsible for the decussation of the corticospinal tract?
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The _____ tract is responsible for transmitting signals to skeletal muscles.
The _____ tract is responsible for transmitting signals to skeletal muscles.
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Match the following components of the pyramidal tract with their respective descriptions:
Match the following components of the pyramidal tract with their respective descriptions:
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What type of stroke is characterized by rapid recovery of consciousness and cortical findings?
What type of stroke is characterized by rapid recovery of consciousness and cortical findings?
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Thrombotic strokes typically involve small vessels.
Thrombotic strokes typically involve small vessels.
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What findings are associated with the inferior division of the Middle Cerebral Artery?
What findings are associated with the inferior division of the Middle Cerebral Artery?
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Hemorrhagic transformation is positive in an _____ stroke.
Hemorrhagic transformation is positive in an _____ stroke.
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Match the features with the type of stroke:
Match the features with the type of stroke:
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Which of the following is a common feature of Complete MCA Syndrome?
Which of the following is a common feature of Complete MCA Syndrome?
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Occlusion of the A2 segment of the Anterior Cerebral Artery typically leads to clinical symptoms.
Occlusion of the A2 segment of the Anterior Cerebral Artery typically leads to clinical symptoms.
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What triad is described as HHH in regards to Complete MCA Syndrome?
What triad is described as HHH in regards to Complete MCA Syndrome?
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The _____ gyrus is associated with apathy and abulia when supplied by the ACA.
The _____ gyrus is associated with apathy and abulia when supplied by the ACA.
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Match the following features to the correct type of lesion:
Match the following features to the correct type of lesion:
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What is the maximum duration for symptoms of a Transient Ischemic Attack (TIA)?
What is the maximum duration for symptoms of a Transient Ischemic Attack (TIA)?
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The ABCD² score is used to predict the risk of stroke following a TIA.
The ABCD² score is used to predict the risk of stroke following a TIA.
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What is the typical evidence seen in a Diffusion weighted MRI (DWMRI) for a minor stroke?
What is the typical evidence seen in a Diffusion weighted MRI (DWMRI) for a minor stroke?
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In TIA patients, if the blood pressure is / mm Hg at the initial evaluation, it scores 1 point on the ABCD² scoring system.
In TIA patients, if the blood pressure is / mm Hg at the initial evaluation, it scores 1 point on the ABCD² scoring system.
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Match the following ABCD² score criteria with the corresponding points:
Match the following ABCD² score criteria with the corresponding points:
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Which of the following symptoms is associated with unilateral involvement of the posterior cerebral artery?
Which of the following symptoms is associated with unilateral involvement of the posterior cerebral artery?
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Anton syndrome involves complete visual loss with no pupillary reaction.
Anton syndrome involves complete visual loss with no pupillary reaction.
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What is the syndrome known for causing chronic burning pain in the upper limb due to thalamogeniculate artery occlusion?
What is the syndrome known for causing chronic burning pain in the upper limb due to thalamogeniculate artery occlusion?
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The feature characterized by missing the larger context while focusing on details is known as _____ syndrome.
The feature characterized by missing the larger context while focusing on details is known as _____ syndrome.
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Match the following symptoms with their corresponding syndromes:
Match the following symptoms with their corresponding syndromes:
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Which artery provides additional branches to the anterior choroidal artery?
Which artery provides additional branches to the anterior choroidal artery?
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The middle cerebral artery supplies the sylvian fissure and is associated with global aphasia when both divisions are stroked.
The middle cerebral artery supplies the sylvian fissure and is associated with global aphasia when both divisions are stroked.
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What is the impact of a stroke in the inferior division of the middle cerebral artery?
What is the impact of a stroke in the inferior division of the middle cerebral artery?
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The _______ artery is responsible for the longest branch, known as the recurrent arterial artery of Heubner.
The _______ artery is responsible for the longest branch, known as the recurrent arterial artery of Heubner.
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Match the following brain arteries with their respective functions:
Match the following brain arteries with their respective functions:
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Which statement best describes the branches of the posterior cerebral artery?
Which statement best describes the branches of the posterior cerebral artery?
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The middle cerebral artery's superior division stroke causes C/L Hemiplegia with Broca's aphasia.
The middle cerebral artery's superior division stroke causes C/L Hemiplegia with Broca's aphasia.
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Identify one common effect of a stroke affecting both divisions of the middle cerebral artery.
Identify one common effect of a stroke affecting both divisions of the middle cerebral artery.
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Striate branches from the _______ cerebral artery are involved in feeding into the choroidal arteries.
Striate branches from the _______ cerebral artery are involved in feeding into the choroidal arteries.
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Which artery connects with branches from the internal carotid artery and serves the anterior limb?
Which artery connects with branches from the internal carotid artery and serves the anterior limb?
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Study Notes
Watershed Territories
- Watershed areas in the brain are prone to infarcts due to reduced blood flow.
- Factors contributing to infarcts in these areas include hypoalbuminemia, sudden hypotension, and dehydration.
- Adequate hydration is crucial for preventing these infarcts.
- ACA: Anterior Cerebral Artery
- MCA: Middle Cerebral Artery
- PCA: Posterior Cerebral Artery
- LCA: Left Common Artery (likely an error in the original document).
Approach to Upper Motor Neuron (UMN) Lesion
- Corticobulbar fibers merge on cranial nerve (CN) nuclei.
- Bilateral (B/L) involvement leads to pseudobulbar palsy, often seen in Amyotrophic Lateral Sclerosis (ALS).
- Unilateral (U/L) involvement is usually asymptomatic due to bilateral representation.
- Exception: CN VII (facial nerve) - Lesion in internal capsule or cortex results in contralateral (C/L) innervation only for the lower half.
- Diagram A (Supranuclear Lesion/UMN): Demonstrates a person with a drooping mouth and deviation of the mouth angle, affecting the upper motor neurons.
- Diagram B (Lower Motor Neuron (LMN) lesion/Facial Nerve lesion): Shows a person with a drooping mouth and deviation of the mouth angle, affecting the lower motor neurons, which can cause Bell's Palsy.
- Motor Homunculus: ACA lesions affect the lower limb, while MCA lesions affect the upper limb and face.
Clinical Features:
- Pyramidal pattern of weakness:
- UMN facial nerve palsy involves the lower half, sparing the upper half.
- Voluntary fibers (skilled learned actions) are affected more than emotional fibers.
- Deglutition and articulation are not affected.
- Upper limb:
- Shoulder abduction lost, leading to adduction.
- Elbow extension lost, leading to flexion.
- Supination lost, leading to pronation.
- Wrist dorsiflexion lost, leading to palmar flexion.
- External rotation lost, leading to internal rotation.
- Lower limb:
- Hip adduction and flexion lost, leading to abduction.
- Internal rotation lost, leading to external rotation.
- Knee flexion lost, leading to extension.
- Foot dorsiflexion lost, leading to plantar flexion.
- Eversion lost, leading to inversion.
- Tone: Circumduction gait.
- Pyramidal lesion - Clasp knife spasticity.
- Spasticity: Velocity and length-dependent resistance to movement in one direction (initial part of movement).
- Rigidity: Resistance to movement in both directions.
- Types of Spasticity: Clasp knife.
- Types of Rigidity: Lead pipe/cog wheel.
- Root values:
- C5, C6: Biceps jerk.
- C7: Triceps jerk.
- C8, T1: Finger flexion.
- L3, L4: Knee jerk.
- S1: Ankle jerk.
Active Space
- Differentials:
- Internal capsule lesions cause dense hemiplegia, hemisensory loss, homonymous hemianopia, 7th CN palsy (more prominent), and absence of cortical findings.
- Brain Stem Lesions: Crossed hemiplegia - left/right (I/L) lower motor neuron (LMN) cranial nerve (CN) nuclei + left/right (C/L) weakness.
- Spinal Cord Lesions: Bilateral (BIL) involvement at a specific level of lesion.
Upper Motor Neurons
- Descending fibers merge on Anterior Horn Cell (AHC) in the spinal cord and Cranial Nerve (CN) nuclei in the brainstem.
Functions
- Corticospinal tract: Integrates highly skilled, fine, discrete movements of distal extremities, supplies lower centers with inhibitory impulses.
- Lesion in the spinal cord: LMN feature at the level, UMN feature below the level.
- Extrapyramidal system: Maintains tone and posture, inhibits proximal and antagonistic muscles.
Tracts/Fibers Included
- Pyramidal tract / Corticospinal Tract (CST) merges on Anterior Horn Cell (AHC).
- Extrapyramidal Fibers:
- Rubrospinal: Lateral white matter.
- Vestibulospinal.
- Tectospinal.
- Reticulospinal: Ventral white matter.
Pyramidal Tract Pathway
-
Cortex:
- Primary motor cortex (30%): Pyramidal cells of Betz (lowest threshold).
- Premotor/supplementary motor cortex (30%).
- Primary sensory cortex (40%).
-
Sub-cortex: Pre-central gyrus.
-
Corona Radiata.
-
Internal Capsule: Anterior 2/3rd of posterior limb, accompanied by Corticonuclear and corticorubral fibers.
-
Midbrain: Superior colliculus, Oculomotor nucleus, Tectum, Tegmentum.
-
Brainstem: Cerebral peduncle, Medulla, Crus cerebri, Red nucleus (decussation of rubrospinal tract), Oculomotor nerve.
-
Lateral Corticospinal Tract: To skeletal muscles.
-
Anterior Corticospinal Tract.
-
Key:
- Upper motor neuron: (Yellow arrow).
- Lower motor neuron: (Black arrow).
-
Decussation (Crossing over):
- Pons: Basilar part.
- Medulla: Decussation at pyramidal level in caudal medulla.
-
Distribution to Spinal Cord: Cervical (50%), Thoracic (40%), Lumbosacral (30%).
-
Trochlear N.(nerve) is not seen at the superior colliculus level of the midbrain.
-
Other important structures labeled: Cerebral aqueduct, Medial longitudinal fasciculus (Lemnisci), Substantia nigra.
Approach to UMN Lesion: Stroke
- Embolic vs Thrombotic Stroke:
Feature Embolic Stroke Thrombotic Stroke Weakness Rapid recovery of consciousness & cortical findings Weakness evolves over 48-72 hr Multiple lesions + - Grey matter involvement - white matter interphase + - Hemorrhagic transformation + - Vessels involved Small vessel Large vessel Thrombectomy + - Prognosis Better - Weakness evolving beyond 72 hrs: Bleeding/tumor.
Middle Cerebral Artery (MCA) Stroke
- From Middle Cerebral Artery (MCA):
- mi/Lenticulostriate artery:
- Internal capsule findings:
- Superior division: Brocas Aphasia.
- Inferior division: Wernickes Aphasia (without weakness).
- Internal capsule findings:
- Complete MCA:
- Weakness.
- Hemianopia.
- Hemisensory loss.
- Cortical findings.
- Global aphasia.
- mi/Lenticulostriate artery:
-
- = Positive
-
- = Negative
- C/L = Contralateral
M Segment
- Supplies: Internal capsule, Caudate nucleus, Putamen, Globus pallidus.
Complete MCA Syndrome
- Involvement of m1 + m2 + m3 Segment.
Complete MCA Syndrome vs Internal Capsule Lesions
| Complete MCA Syndrome | Internal Capsule Lesions |
|---|---|
| Common features: | |
| * HHH triad | * Dense Hemiplegia (UL = LL) |
| Different features: | |
| * Aphasia | |
| * Agnosia | |
| * Apraxia | |
| * LOC and seizure | |
| * Non dominant findings: unstructured/dressing apraxia | |
| * Hemispatial neglect |
Anterior Cerebral Artery (ACA)
- Al Segment: Proximal to Anterior communicating artery
- Structures supplied: Hypothalamus (Anterior hypothalamus), Caudate lobe (Antero-inferior part of Head of caudate).
- A2 Segment: Distal to Anterior communicating artery
- Structures supplied: Internal capsule (Anterior limb), Medial/Cerebral surface: C/L hemiplegia (LL > UL), Paracentral lobule: urinary incontinence, Cingulate gyrus: Apathy, Abulia.
- Occlusion of segment: No clinical symptoms due to significant collaterals.
Vascular Anatomy of Brain: Blood Supply
- Anterior Choroidal Artery (Anterior Choroidal a.): Supplied by striate branches of the middle cerebral artery and the recurrent branch of the anterior cerebral artery. Branches from the internal carotid and posterior communicating arteries.
- Anterior Cerebral Artery (Anterior cerebral A.): Striate branches of the anterior cerebral artery (including the longest branch, recurrent arterial artery of Heubner). Shares branches with the middle cerebral artery, connects directly with branches from the internal carotid. Anterior Limb: Striate branches from the anterior cerebral artery.
- Middle Cerebral Artery (Middle cerebral A.): Striate branches from the middle cerebral artery, including the large Charcot artery (cerebral haemorrhage) and connecting with the anterior choroidal artery. Branches connect with the anterior cerebral branches. Posterior Limb: Striate branches from the middle cerebral artery, including the large Charcot artery of cerebral haemorrhage and the anterior choroidal.
- Posterior Cerebral Artery (Posterior cerebral A.): Striate branches from the posterior cerebral artery, connecting with the anterior choroidal artery.
- Geniculate: Striate branches from the Anterior cerebral artery and the internal carotid artery.
- Retrolentiform and Subleniform Parts: Striate branches from the posterior cerebral artery, feeding into the choroidal arteries.
Middle Cerebral Artery Segment (MA SEGMENT)
| Division | Stroke Impact |
|---|---|
| Superior | C/L Hemiplegia with Broca's aphasia (speech production difficulty) |
| Inferior | C/L Hemiplegia with Wernicke's aphasia (understanding language difficulty; without weakness) |
| Both Divisions | C/L Hemiplegia with global aphasia (loss of spoken and written languages; loss of comprehensions) |
- Injury: "HHH triad" injury with mild forms and predominant hemisensory loss.
- Location: Middle cerebral artery supplies the sylvian fissure, a major sulcus in the brain.
Approach to Stroke
- Stroke: Abrupt onset of focal/global neurological deficit (FND) lasting ≥ 24 hrs, predominantly vascular origin with evidence of infarction or hemorrhage.
TIA (Transient Ischemic Attack)
- Definition: Episode of neurological dysfunction caused by focal brain/retinal ischemia lasting < 1 hour without evidence of infarction.
- Pt. with TIA → Diffusion weighted MRI (DWMRI): Normal = No stroke (only TIA), Hyperintense Lession = minor stroke (Even if clinically recovered).
ABCD² Score
| ABCD² score | Points |
|---|---|
| Age > 60 years | 1 |
| BP = 140/90 mm Hg at initial evaluation | 1 |
| Clinical features of the TIA: | |
| Speech disturbance without weakness, or Unilateral weakness | 1 |
| Duration of symptoms: | |
| 10-59 min, or > 60 min | 1 |
| Diabetes mellitus in patient's history | 1 |
Risk of stroke following TIA with various ABCD² scores:
| Total risk | Scores 2 days | Scores 7 days | Scores 90 days |
|---|---|---|---|
| Low | 0-3 | 1.0 | 1.2 |
| Moderate | 4-5 | 4.1 | 5.9 |
| High | 6-7 | 8.1 | 12 |
Notes:
- Dual antiplatelet therapy indications in neurology:
- TIA.
- Mini stroke.
- ICAD (Intracranial Atherosclerotic Disease): > 50% occlusion of vessel.
- Every other condition: Single antiplatelet therapy.
- Aspirin / Ticagrelor > Clopidogrel.
Posterior Cerebral Artery
- Corticosensory loss (Partial).
- Gait apraxia (B/L involvement): Also seen in Normal Pressure Hydrocephalus.
- Primitive reflex: Loss of C/L grasp & sucking reflex.
Posterior Cerebral Artery: Vascular Anatomy of Brain
-
- U/L Involvement: Visual agnosia, Peduncular hallucinations (complex visual hallucinations), Splenium: Alexia without agraphia, Hippocampus: memory disturbances.
-
- B/L involvement: Anton syndrome: Cortical blindness with pupillary sparing, Balint's syndrome: Optic ataxia (overshooting of visual field), oculomotor apraxia, simultanagnosia (missing forest for the trees), palinopsia (abnormal persistence of an image in time).
Occipital Lobe Involvement (characteristic of Pa lesion)
- C/L homonymous hemianopia (congruent hemianopia).
- Macular sparing.
Types of posterior circulation:
| Type | Description |
|---|---|
| Type I | Involves the artery of percheron (AOP).Infrat - drowsy/confusion + vertical gaze palsy + memory disturbance |
| Type IIA | ... |
| Type IIB | ... |
| Type III | ... |
Syndromes:
- Dejerine Roussy syndrome (AKA burning hand syndrome): Thalamogeniculate artery occlusion. Features: C/L hemisensory loss, burning pain in ULELL.
- Ataxia with agraphia: Gerstmann syndrome.
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Description
This quiz explores the critical concepts related to watershed territories in the brain and their vulnerability to infarcts due to reduced blood flow. It also covers upper motor neuron lesions, their clinical implications, and the anatomy related to various cranial nerves. Test your knowledge on these essential neuroanatomical themes.
