Source:http://linkedlifedata.com/resource/umls/id/C0003550
MSH: An aphasia characterized by impairment of expressive language (speech, writing, signs) and relative preservation of receptive language abilities (i.e., comprehension). This condition is caused by lesions of the motor association cortex in the frontal lobe (Broca's area and adjacent cortical and white matter regions). The deficits range from almost complete muteness to a reduction in the fluency and rate of speech. CEREBROVASCULAR ACCIDENTS (in particular INFARCTION, MIDDLE CEREBRAL ARTERY) are a relatively common cause of this condition. (From Adams et al., Principles of Neurology, 6th ed, pp478-9)