In 1920 Weed1 reported on the occurrence in animals of calcified plaques and of the islands of arachnoidal tissue in which they form. He came to the conclusion that the plaques, within islands of arachnoid cells arranged in concentric whorls, are a phenomenon of advancing age. The process of calcification he concluded to be a degenerative one within the whorls, similar to the deposition of calcium elsewhere as a result of degeneration. There is little doubt that the plaques are formed as deposits of calcium in the islands of arachnoid cells (fig. 1). Observations by Weed1 and by Cushing and Weed 2 have demonstrated this fact satisfactorily.
This report concerns itself with the incidence, sites of occurrence and possible significance of calcified arachnoidal plaques in the spinal arachnoid of man. The material was obtained from 25 consecutive routine autopsies at the Mallory Institute of the Boston City Hospital.
HERREN Y. OCCURRENCE AND DISTRIBUTION OF CALCIFIED PLAQUES IN THE SPINAL ARACHNOID IN MAN. Arch NeurPsych. 1939;41(6):1180-1186. doi:10.1001/archneurpsyc.1939.02270180108010