Neuroanatomy
Dr Raymond Chang
This is a set of cranial MRIs from a patient with osmotic demyelination syndrome, formerly called central pontine myelinolysis. Osmotic demyelination syndrome occurs when wide fluxes in serum sodium levels are induced by too rapid correction of hyponatremia. Oligodendrocytes, which forms the myelin sheaths, are particularly vulnerable to osmotic changes. If the osmotic stress is…
Subtitles in English for this video can be displayed by clicking on (first button on the bottom right hand corner of the video). Stereopsis (three dimensional vision) is important in our every day lives. This ability is dependent on aligning both foveae on the same object with slightly dissimilar perspectives to give a perception of depth….
Bilateral watershed infarct The non-contrast CT brain shown is from a patient with bilateral watershed infarct. Here, chronic ischaemic changes can be seen along the external or cortical watershed zones (Figures 1 and 2). These “borderzones” is where the terminal vasculature of the anterior cerebral artery and middle cerebral artery meet as well as where the middle…
Dr Gilberto Leung and Dr Gary Lau Subtitles in English for this video can be displayed by clicking on (first button on the bottom right hand corner of the video). Our level of consciousness is governed by our cerebral cortex as well as the subcortical ascending reticular formation. Patients with normal consciousness have a high level…
As one can appreciate in this video, this middle-aged man has right-sided intention tremor. The right index finger shows exaggerated tremor when approaching the target, i.e. his nose and physician’s finger. Please note that the examiner should place his finger at around one arm’s length from the patient. This is so that the patient could…
Subtitles in English for this video can be displayed by clicking on (first button on the bottom right hand corner of the video). The size of the pupillary aperture at any point in time is dependent on a balance between sympathetic tone, parasympathetic tone, the light reflex and the near reflex. The light reflex is an…