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…
In this patient, there is a mild esotropia on neutral gaze as the left eye is slightly deviated medially. There is impaired left eye abduction resulting in diplopia when the patient is instructed to look towards the left. Discussion of the sign Abduction of the eye is controlled by the lateral rectus muscle, which is…
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…
The gait is wide-based and the patient requires assistance from the physician for stabilization. The patient cannot turn within one or two steps but requires multiple steps. The physician then asks the patient to perform tandem-walking at the end of the video but the patient is unable to do so due to severe instability. The…
Subtitles in English for this video can be displayed by clicking on (first button on the bottom right hand corner of the video). Inspection of the Lower Limbs After positioning the patient on the bed and ensuring adequate exposure, the lower limbs should be inspected as follow: The examiner should stand at the end of the bed and…
In the first video, the patient has both horizontal nystagmus and vertical “down-beat” nystagmus. In the second video, the patient has a torsional nystagmus when looking to her right hand side. Discussion of the sign Nystagmus is defined as a rhythmic oscillation of the eyes. It usually consists of a slow drifting phase in one direction and a…