- A sharply pointed shaft, usually with a three-sided point. A trocar may be used within a cannula, a hollow tube, designed to be inserted into a vein, artery, bone marrow or body cavity. The word trocar is derived from the French "trois" (three) + "carre" (side).
* * *An instrument for withdrawing fluid from a cavity, or for use in paracentesis; it consists of a metal tube (cannula) into which fits an obturator with a sharp three-cornered tip, which is withdrawn after the instrument has been pushed into the cavity; the name t. is usually applied to the obturator alone, the entire instrument being designated t. and cannula. [Fr. trocart, fr. trois, three, + carre, side (of a sword blade)]- Hasson t. a blunt t. inserted into the peritoneal cavity after making a small celiotomy; used for insufflation and introduction of a laparoscope.
* * *tro·car also tro·char 'trō-.kär n a sharp-pointed surgical instrument fitted with a cannula and used esp. to insert the cannula into a body cavity as a drainage outlet
* * *n.an instrument used combined with a cannula to draw off fluids from a body cavity (such as the peritoneal cavity). It comprises a metal tube containing a removable shaft with a sharp three-cornered point; the shaft is withdrawn after the trocar has been inserted into the cavity.
* * *tro·car (troґkahr) [Fr. trois quarts three quarters] a sharp-pointed instrument equipped with a cannula, used to puncture the wall of a body cavity and withdraw fluid.
Medical dictionary. 2011.