Source / episode info

• **Episode:**58
• **Title:**Divine Intervention Episode 58 – Neurology Clerkship Shelf Review Part 7
• **Published:**2018-10-19
• Source:Episode page

One-liner

This episode provides a comprehensive review of high-yield neurological concepts, including the ascending spinal tracts (dorsal column/spinothalamic), detailed localization syndromes based on vascular anatomy (Circle of Willis), and critical distinctions between UMN and LMN cranial nerve deficits.

High-yield summary

• Dorsal Column-Medial Lemniscus System: Carries fine touch, vibration, and proprioception; ascends ipsilaterally in the spinal cord via fasciculus gracilis (lower body) or fasciculus cuneatus (upper body), synapses at Nuclei Gracilis/Cuneatus, then decussates to form the Medial Lemniscus.
• Spinothalamic Tract: Carries pain and temperature information; enters the spinal cord and synapses immediately in the anterior white commissure before ascending contralaterally as the lateral spinothalamic tract.
• Lateral Pontine Syndrome (LPS): Any lesion affecting the lateral brainstem (e.g., AICA infarct) will cause deficits involving CN V, VII, VIII, loss of pain/temperature sensation, and Horner syndrome due to the proximity of these structures in the lateral pons.
• Visual Field Defects: Transsection of the optic chiasm results in bitemporal hemianopsia (loss of temporal fields); transsection of the optic tract results in homonymous hemianopsia.
• Cranial Nerve VII Localization: UMN lesions cause contralateral lower facial droop due to bilateral innervation of the frontalis muscle; LMN lesions affect both upper and lower face.
• Post-Lumbar Puncture Headache (PLPH): Caused by CSF leak leading to decreased intracranial/intraspinal pressure, treated initially with conservative measures or caffeine, potentially requiring a blood patch.

Learning objectives

• Trace the ascending pathways for fine touch and proprioception (Dorsal Column).
• Differentiate between the clinical presentations of UMN vs LMN cranial nerve palsies.
• Identify the anatomical structures involved in the Circle of Willis and their associated syndromes.
• Interpret visual field defects based on the location of optic pathway lesions (chiasm, tract, radiation).
• Recognize the pathophysiology and management of post-lumbar puncture headache.