Definition of "obex" [obex]

• The point in the human brain at which the fourth ventricle narrows to become the central canal of the spinal cord. (noun)

Wiktionary.org : Text is available under the Creative Commons Attribution-ShareAlike License

• "The obex is a thin, triangular, gray lamina, which roofs in the lower angle of the ventricle and is attached by its lateral margins to the clavæ."
• "This maintained divine immutability but had the added bonus of providing symmetry for reprobation and predestination: the determining factor is the presence or absence of an obstacle to grace (obex gratiae)."
• "—The upper portion of the roof is formed by the superior peduncle and the anterior medullary velum; the lower portion, by the posterior medullary velum, the epithelial lining of the ventricle covered by the tela chorioidea inferior, the tæniæ of the fourth ventricle, and the obex."