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Difficulty: HardPhysical Examination Findings

Neurological physical examination is critical for localizing acute ischemic strokes. Match each constellation of physical examination findings with its most likely corresponding occluded vascular territory.

  • Ipsilateral ptosis and miosis, hoarseness, absent gag reflex, and contralateral body loss of pain and temperature sensationPosterior inferior cerebellar artery (PICA)
  • Ipsilateral tongue deviation upon protrusion, contralateral hemiparesis, and contralateral loss of proprioceptionAnterior spinal artery (ASA)
  • Ipsilateral ptosis, resting 'down and out' eye position with mydriasis, and contralateral hemiparesisPosterior cerebral artery (PCA) paramedian branches
  • Ipsilateral complete facial paralysis, inability to abduct the eye, and contralateral hemiparesisBasilar artery paramedian branches
  • Contralateral lower extremity weakness and sensory loss, with relative sparing of the upper extremity, accompanied by urinary incontinenceAnterior cerebral artery (ACA)

Answer

The correct matches correlate classic neurological examination findings to their respective vascular territories: Lateral Medullary (Wallenberg) syndrome to PICA, Medial Medullary syndrome to ASA, Midbrain (Weber) syndrome to PCA paramedian branches, Caudal Pontine syndrome to Basilar paramedian branches, and medial frontoparietal cortical strokes to ACA.
Crossed signs (ipsilateral cranial nerve palsies and contralateral long tract deficits) indicate a brainstem lesion. CN III localization points to the midbrain (PCA paramedian branches). CN VI/VII localizations point to the pons (Basilar paramedian branches). CN XII localization points to the medial medulla (ASA), while the nucleus ambiguus and sympathetic fibers point to the lateral medulla (PICA). Cortical strokes lack crossed cranial nerve signs; ACA strokes preferentially cause contralateral lower extremity weakness and sensory loss, along with incontinence, due to medial cortex involvement.

Step-by-Step Solution

1
Analyze the cranial nerve deficits to determine the rostrocaudal level of the brainstem lesion.
Oculomotor (CN III) deficits localize to the midbrain. Abducens (CN VI) and Facial (CN VII) deficits localize to the pons. Glossopharyngeal (CN IX), Vagus (CN X), and Hypoglossal (CN XII) deficits localize to the medulla.
Cranial nerve nuclei have strict vertical anatomical positions within the brainstem.
2
Evaluate the long tract signs (motor and sensory) to establish the medial-lateral position of the lesion.
Corticospinal tract (motor) and medial lemniscus (proprioception) deficits indicate a medial lesion. Spinothalamic tract (pain/temperature) and sympathetic chain (Horner syndrome) deficits indicate a lateral lesion.
Vascular supply to the brainstem is strictly segregated into paramedian (medial structures) and circumferential (lateral structures) arterial branches.
3
Synthesize the neuroanatomical localization to deduce the occluded vascular territory.
A medial medullary lesion maps to the ASA, a lateral medullary lesion to the PICA, a medial pontine lesion to basilar paramedian branches, and a midbrain lesion to PCA paramedian branches. Deficits sparing cranial nerves but disproportionately affecting the contralateral leg map to the ACA.
Understanding distinct cerebrovascular territories is necessary to establish the etiology of the physical examination findings.

Key Concept

Neuroanatomical localization of acute ischemic strokes using cranial nerve and long tract physical examination findings
Estimated Time:1m 30s
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Physical Examination Findings

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