paracentesis

[Lat., from Gr. paraken tes is tapping for dropsy, or couching for cataract ( Galen ): pref. para, and Gr. kentésis pricking; kenteō -to prick.] Surg.: The operation of tapping. It is performed by a trocar and canula (q. v.). Paracen tes is abdominis is the tapping of the abdomen to withdraw the fluid effused in dropsy. Par centesis thoracis , the tapping of the breast to remove pus in pleurisy. păr-a-çen-tric, a . & s . [Pref. para- , and Eng centric; Fr. paracentrique .] A. As adj .: Deviating from circularity; chang ing the distance from a center. B. As subst.: A curve having the property that, when its plane is placed vertically, a heavy body descending along it, urged by the force of gravity, will approach to or recede from a fixed point, or center, by equal distances in equal times.