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[prop-toh-sis] /prɒpˈtoʊ sɪs/
noun, Pathology
the forward displacement of an organ.
1670-80; < New Latin < Greek próptōsis a fall forward. See pro-2, ptosis
Related forms
[prop-tohst] /ˈprɒp toʊst/ (Show IPA),
[prop-tot-ik] /prɒpˈtɒt ɪk/ (Show IPA),
adjective Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2015.
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British Dictionary definitions for proptosis


noun (pl) -ses (-siːz)
(pathol) the forward displacement of an organ or part, such as the eyeball See also exophthalmos Compare prolapse
Word Origin
C17: via Late Latin from Greek, from propiptein to fall forwards
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
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proptosis in Medicine

proptosis prop·to·sis (prŏp-tō'sĭs)
n. pl. prop·to·ses (-sēz)
Forward displacement of an organ, especially an eyeball.

prop·tot·ic (-tŏt'ĭk) adj.
The American Heritage® Stedman's Medical Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
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Encyclopedia Article for proptosis


abnormal protrusion of one or both eyeballs. The most common cause for unilateral or bilateral exophthalmos is thyroid eye disease, or Graves ophthalmopathy. The proptosis arises from inflammation, cellular proliferation, and accumulation of fluid in the tissues that surround the eyeball in its socket, or orbit. The vast majority of people with Graves ophthalmopathy also have (or will later develop) thyroid dysfunction. Other causes of exophthalmos include other orbital inflammatory conditions, spread of infection from the paranasal sinuses or teeth, trauma, various orbital tumours, and vascular (blood vessel) abnormalities of the orbit. It should also be noted that "prominent" eyes can be a normal inherited trait in certain families

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Encyclopedia Britannica, 2008. Encyclopedia Britannica Online.
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