(Greek > Latin: to let down, to insert, to thrust in [kata, "down" plus hienai, "to send"])

arterial catheter (s) (noun), arterial catheters (pl)
A tube inserted into an artery to measure pressure, remove blood, inject medication or a radiographic contrast media, and be used to perform an interventional radiological procedure: Jim's doctor told him that a long slender flexible tube or arterial catheter would be used for inserting into one of his arteries so the abnormal narrowing that he has can be expanded because his condition could reduce blood flow and even cause tissue damage.
balloon catheter (s) (noun), balloon catheters (pl)
A kind of flexible sac with one or more of them being used to apply pressure on an organ or vessel and which functions either for draining fluid from or injecting it into a part of the body for therapeutic purposes: A kind of balloon catheter, with a sausage-shaped balloon, is used to expand narrow arteries which can avoid the need for surgery; although the narrowing of the vessel may occur again.

Another application of the balloon catheter is to treat the bleeding of enlarged veins in the esophagus or stomach, a life-threatening condition of some kinds of liver disease.

bladder catheter (s) (noun), bladder catheters (pl)
A flexible plastic tube that is inserted into the hollow organ located in the lower abdomen which stores urine: Dr. Atherton inserted a bladder catheter into his patient's bladder so continuous urinary drainage could take place.
cardiac catheter (s) (noun), cardiac catheters (pl)
A long, fine, flexible tube designed for insertion into a peripheral blood vessel through which it can then be manipulated under X-ray control into the heart: The cardiac catheter is used for registration of pressures, sampling of blood, or rapid injection of radiopaque substances which will outline the chambers and blood vessels of the heart.
catheter (s) (noun), catheters (pl)
In medicine, a flexible tube or tubes that are inserted through a narrow opening into a body cavity, particularly the bladder, for removing fluid: One of the main definitions of catheter is that it is a tube which is passed into the body for evacuating fluids or for injecting them into body parts for the administration of diagnostic or therapeutic agents.

Catheters may be made of elastic, elastic web, rubber, glass, metal, or plastic.

catheterization (s) (noun), catheterizations (pl)
An insertion of a small tube into a body area to remove fluid, create an opening, widen a passageway, or to administer a drug: Some medical situations require that the use of catheterization or the placement of a tubular device into a duct, blood vessel, or hollow organ of the body for injecting; or for withdrawing fluids, for diagnostic or medical treatment purposes.
catheterize (verb), catheterizes; catheterized; catheterizing
Inserting a flexible tube through a narrow opening into a particular body part: Most of the time, patients are catheterized to the bladder; however, catheterizing is also introduced into the heart, via a blood vessel, in order to diagnose its condition.
catheterostat (s) (noun), catheterostats (pl)
A long, thin stand that is used for storing, cleaning, or sterilizing specialized kinds of surgical tools: The catheterostat holds and sterilizes catheters.
cathetometer (s) (noun), cathetometers (pl)
An instrument for the accurate measurement of small differences of height; especially, of the differences in the height of the upper surfaces of two columns of mercury or other fluid, or of the same column at different times: The cathetometer consists of a telescopic leveling apparatus, that slides up or down a perpendicular metallic standard which is very finely graduated.

The telescope in the cathetometer is raised or lowered in order to see the objects or surfaces, and to determine the differences in vertical height which are then shown on the graduated standard.

filiform-tipped catheter (s) (noun), filiform-tipped catheters (pl)
A long, thin, hollow surgical instrument, that is inserted into a space in the body: A filiform-tipped catheter is one with the leading end that is very slender and flexible in order to facilitate the passage of the catheter through a constricted, angulated, or obstructed tubular structure.
Foley catheter (s) (noun), Foley catheters (pl)
A self-retaining tube that is held in place in the urinary bladder with an inflated balloon: A Foley catheter is constructed so it will stay where it is placed by a surgeon or another medical person in order to diagnose or to treat an ailment.