Neuroanatomy
Dr Raymond Chang
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…
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…
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…
Subtitles in English for this video can be displayed by clicking on (first button on the bottom right hand corner of the video). General Inspection During the general inspection of the cranial nerves, we should look for whether the patient has any ptosis, abnormal eye movements and facial asymmetry. We should also inspect for whether there are any neuro-cutaneous features (for example in patients…
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…