| brainstem | <anatomy> The lowest part of the brain, which merges with the spinal cord. It consists of the medulla oblongata, midbrain and pons. Originally, the entire unpaired subdivision of the brain, composed of (in anterior sequence) the rhombencephalon, mesencephalon, and diecephalon as distinguished from the brain's only paired subdivision, the telencephalon. More recently, the term's connotation has undergone several arbitrary modifications: some use it to denote no more than rhombencephalon plus mesencephalon, distinguishing that complex from the prosencephalon (diencephalon plus telencephalon); others restrict it even further to refer exclusively to the rhombencephalon. From both developmental and architectural viewpoints, the original interpretation seems preferable. (05 Mar 2000) |
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| brainstem auditory evoked potentials | <investigation, physiology> A special neurologic test which measures the brainstem and brains nervous response to auditory stimulation. It is used to evaluate neurologic integrity and hearing in newborns. Can be used in the evaluation of stroke, acoustic neuroma, Meniere's disease and multiple sclerosis Acronym: BAEP (15 Nov 1997) |
| brainstem evoked response audiometry | An electrophysiologic measure of auditory function utilizing responses produced by the auditory nerve and the brainstem to repetitive acoustic stimuli. (05 Mar 2000) |
| brainstem glioma | <oncology, tumour> This primary brain tumour occurs in the pons or the medulla. They account for approximately 15% of brain tumours in children. Symptoms include double vision, facial weakness, vomiting and difficulty walking. Surgery is difficult due to location so radiation therapy and chemotherapy are used. Overall survival is 20 to 30%. (27 Sep 1997) |
| brainstem haemorrhage | Haemorrhage into the pons or mesencephalon, often secondary to brainstem distortion by transtentorial herniations due to rapidly expanding intracranial lesions. (05 Mar 2000) |