Neurology · USMLE Step 1 and Step 2

Stroke Localization song

MCA, ACA, PCA & PICA Syndromes - Stroke Localization, as a song. Hear the short teaser here. The full song is on YouTube and Spotify.

Stroke Localization

Full song on YouTube ↗Spotify ↗

Key points in this song10

MCA stroke causes contralateral hemiplegia and hemisensory loss with face and arm > leg involvement, plus contralateral homonymous hemianopia and gaze deviation toward the side of the lesion.
Dominant (left) MCA stroke causes Broca aphasia (frontal branch) or Wernicke aphasia (temporal branch); non-dominant MCA stroke causes hemispatial neglect and anosognosia.
ACA stroke causes contralateral hemiplegia and hemisensory loss with leg > arm > face involvement, due to infarction of the medial cortex supplied by the pericallosal and callosomarginal arteries.
ACA stroke classically causes abulia, urinary incontinence, and contralateral grasp reflex due to frontal lobe involvement; bilateral ACA infarction can cause akinetic mutism.
PCA stroke causes contralateral homonymous hemianopia with macular sparing (due to dual supply of the occipital pole by MCA), along with visual agnosia and alexia without agraphia in dominant hemisphere lesions.
PCA infarction involving the thalamus causes contralateral hemisensory loss and thalamic pain syndrome (Dejerine-Roussy); midbrain involvement causes ipsilateral CN III palsy with contralateral hemiplegia (Weber syndrome).
PICA occlusion causes lateral medullary (Wallenberg) syndrome: ipsilateral facial pain/temperature loss, ipsilateral Horner syndrome, ipsilateral ataxia, dysphagia, dysarthria, and contralateral body pain/temperature loss, with sparing of motor function and vibration/proprioception.
The key distinguishing feature of Wallenberg syndrome is crossed sensory loss — ipsilateral face and contralateral body — due to involvement of the spinal trigeminal nucleus and the already-crossed spinothalamic tract.
AICA occlusion mimics PICA but additionally causes ipsilateral sensorineural hearing loss and facial nerve palsy due to involvement of the cochlear nuclei and CN VII fascicles in the lateral pons.
Lacunar infarcts from small vessel disease (hypertension, diabetes) classically produce pure motor hemiplegia (posterior limb of internal capsule), pure sensory stroke (thalamus), or ataxic hemiparesis (pons or internal capsule), without cortical signs.