. All four llrntis are observed lor responses to pain and the besi response is recorded.

Scale. Supra-orbital pressure is a useful centra] stimulus and nail bed pressure a peripheral one. All four llrntis are observed lor responses to pain and the besi response is recorded. Asymmetry should be noted arid is importani In idenentifying localization. BRAIN STEM FUNCTION 1. Pupils Normally reacting pupils - Metabolic causes or drug overdosage [except glutethlrride and amphetamine). [il] Unequal pupils - Unless proved otherwise, a dilated pupil indbates a hernlaled temporal lobe stretching the 3rd nerve on that side. till) Bilateral dialed pupils - End stage of progressive lentorial hemiation. Also glulethimide, atropine and amphetamine poisoning. (Iv) Bilateral pinpoint pupils - Intraponline hemorrhage, opiates. 2.. Cornea! response - is usually retained until very deep coma. If it Is absent In patient in light coma, Ihe cause of coma may be drug intoxication. Loss of cornea! reflex in absence of drug overdosage is a poor prognostic indicator. 3. Spontaneous eye movements - (a) Conjugate deviation of the eyes suggests a focal hemispheric or brainstern lesion. (b) Depression of eye movements may occur in mlotraln damage at level of Ihe tectum and occasionally In metabolic coma.