How to place a urinary catheter (in-and-out or Foley)

It sounds silly, but I have found that people often struggle to place urinary catheters in female patients, especially patients with higher BMIs. Once you understand what landmarks to look for, though, you’ll be able to get the catheter in the right spot every time!

Image created by Bruce Blaus and used under the Creative Commons license.


The first step in placing a catheter is to identify the urethral meatus.

  • Place the first two fingers of your non-dominant hand at the introitus (the opening of the vagina) and separate the labia minora.
  • Now keep that hand there – it doesn’t move from now until the catheter is in!
  • Identify the anterior commissure (where the labia minora come together anteriorly).
  • Look directly posterior (down, if the patient is on her back) from the anterior commissure. Note that the mucosa of the vestibule is smooth, while the mucosa of the anterior vaginal wall is rugated (covered in lots of transverse folds).
  • The urethral meatus can be found in the midline, directly posterior to the anterior commissure, where the smooth mucosa of the vestibulemeets the rugated mucosa of the vagina. 
  • Clean the urethral meatus (typically this is done with iodine swabs)
  • Apply lube to the tip of the catheter (typically by dunking the tip in a puddle of lube in the kit)
  • Introduce the catheter with your dominant hand, holding it like a pencil
  • Advance the catheter until you see urine
  • With an indwelling (Foley) catheter that has a balloon, advance another centimeter or two to ensure the balloon tip of the catheter is all the way in the bladder, then inflate the balloon.



Q: How do I know which port to inflate on the indwelling catheter?

Image created by Olek Remesz and used under the Creative Commons license.

A: A balloon-tip catheter will end in a Y with two tips. One tip will be narrow and will have a colored plastic band with information about the catheter printed on it (such as the volume of balloon). This is the part of the catheter labeled “balloon port” in the image above. This port is connected to the balloon. The other tip is wider, and is usually a “flaring out” of the catheter material (labeled urine drainage port in the image above). The tubing that connects to the drainage bag is pushed onto this wider tip and help in place by friction.

Q: Does it matter what fluid I inflate the balloon with?

A: Well… it depends. Most people will tell you to use sterile water (instead of the more easily available normal saline). The thought behind this is that if the balloon remains in place for a long time, the saline could potentially crystalize inside the balloon, making it more difficult to deflate the balloon and remove the catheter. This is why any Foley kit that you open will contain a syringe of sterile water. Practically speaking, if the catheter is only staying in for a few hours, such as for a c-section, it probably doesn’t matter.

Q: What sizes of catheters are normally used?

A: Urinary catheters are described in French (Fr). The smaller the number, the smaller the diameter. For adults, most Foley kits contain a 16 Fr catheter. 14 Fr catheters (slightly smaller) are also commonly used for comfort.

Q: What materials are available?

A: Most Foley kits contain a latex catheter. Silicone catheters are also available for latex-sensitive patients. The silicone catheters are typically transparent, whereas the latex catheters are typically mustard yellow.


Please feel free to post any questions or tips below!

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