Localization & Neuro Exam
The habit this site is named for: working out where the problem is before deciding what it is. Twelve interactive modules on localization and the neurologic examination in children, from telling upper from lower motor neuron weakness to building a differential.
When a child stops walking, it is tempting to reach straight for a diagnosis. Neurologists have long done something else first. They use the examination to work out where in the nervous system the problem must be, use the story of how it unfolded to judge when and how fast, and only then ask what it is. These twelve modules teach that habit with figures you can experiment with, each one calculated from a model of the anatomy so that you can change a finding and watch the answer move.
If you only have time for part of the course, these six modules carry the core method, and the others build on them.
No findings yet: every level is possible.
A teaching model of classical rules (Brazis 2011; DeMyer; Peredo 2009). Each rule's exceptions are listed under its finding. Real patients can have more than one lesion.
Modules 1 to 3 make the case for localizing before diagnosing, treat the examination as a set of experiments, and teach the first and most useful split, between upper and lower motor neuron.
Why neurology looks for the lesion before it names the disease, and how that old method has to adapt when the nervous system being examined is still growing.
How to run the neurologic examination as a series of experiments on circuits, from watching a child before touching them and turning tests into play to reading the infant reflexes that are meant to come and go.
How tone and reflexes separate an upper from a lower motor neuron lesion, where those rules bend, and how the same reasoning sorts the floppy infant.
Modules 4 and 5: the motor unit, and the maps of roots, plexus and nerves.
The four parts of the motor unit where weakness can begin, from the anterior horn cell to the muscle, and the pattern each one leaves on the examination.
Every limb carries three overlapping maps. This module shows how to choose the muscle or reflex that tells them apart.
Modules 6 to 8: the spinal cord, the brainstem, and the loops of cerebellum and basal ganglia.
Three tracts and the places where they cross account for every cord syndrome, and three independent signs locate the level.
How a crossed pattern of signs places a lesion in the brainstem, how the rule of four simplifies that anatomy, and what changes when the lesion is a child's tumor.
How the cerebellum and basal ganglia shape movement without powering it, how to localize ataxia, vertigo and involuntary movements, and why watching a child walk is the best single test of the motor system.
Modules 9 and 10: the cortex and visual pathway, and what to do when the lesion is everywhere.
How cortical lesions show up in language, attention, gaze, the proportions of a weakness and the visual fields, and how early injury shapes the developing hemisphere.
How to localize a child who cannot cooperate. The module covers the two structures that sustain consciousness, the coma examination as a way of finding the level, metabolic versus structural coma, herniation, and diffuse disease.
Modules 11 and 12 turn an address and a time course into a differential, and then put the method to work on six cases you examine yourself.
How the time course turns a localization into a short list of causes. The module covers the mechanism categories, the where-by-when grid, the child's own clock and functional disorder, which is diagnosed from positive signs like everything else.
Six children to work through from the history and examination to a level, a tempo and a differential, each followed by the attending's debrief.
- Brazis PW, Masdeu JC, Biller J. Localization in Clinical Neurology. 6th ed. 2011.
- Pearl PL, Emsellem HA. Neuro-Logic: A Primer on Localization. 2014.
- Biller J, Gruener G, Brazis PW. DeMyer's The Neurologic Examination: A Programmed Text. 6th ed.
- Fisch A. Neuroanatomy: Draw It to Know It. 2nd ed. 2012.
- Arslan O. Neuroanatomical Basis of Clinical Neurology. 2nd ed. 2014.
- Neurological Clinical Examination: A Concise Guide. 3rd ed. 2012.
Written in our own words, citing these texts by page. For education; not for clinical decision-making.