Category: O

A pelvis distorted because of osteomalacia. A malformed pelvis marked by reduced side-to-side and diagonal dimensions but significantly increased front-to-back measurements.  

A microorganism that is usually harmless but may become pathogenic in certain circumstances, e.g., when it is introduced into a part of the body where it normally does not reside or when it infects an immunocompromised host.  

A parasite such as a virus or rickettsia that can reproduce only when within a living cell, although it may survive outside cells.  

A parasite completely dependent on its host; the opposite of a facultative parasite.  

Paralysis of the extraocular and intraocular muscles. Paralysis affecting the muscles controlling eye movement, the optic nerve, or the ciliary muscle within the eye.  

Pain induced by some external or internal irritant, by inflammation, or by injury to nerves, organs, or other tissues that interferes with the function, nutrition, or circulation of the affected part. It is usually traceable to a definite pathologic process.  

Using a pacemaker to generate a heart rate that is faster than the spontaneous heart rate of the patient. This is used in attempts to capture and terminate tachycardias or, in some cases, to try to trigger and study tachycardias in patients who have suffered them in the past.  

A disease in which the skin of the scalp, especially in the occipital region, falls into thickened folds.  

To convert oxygen to ozone.  

The act of converting to, or impregnating with, ozone.