Definition of "pia mater" []

• The fine vascular membrane that closely envelops the brain and spinal cord under the arachnoid and the dura mater. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "The edema of the brain, irregular pink mottlings of white substance, and an exudative lesion of one focus in the pia mater of the right side suggested an encephalitis more marked on the right side."
• "The frontal pia mater was greatly thickened and, although no gross lesions were noted in the cortex, the microscope brings out marked lesions in the shape of cell losses (especially in suprastellate layers) in all areas examined."