A urine bag, also known as a urinary drainage bag or collection bag, is a medical device used to collect and store urine from the bladder. It is commonly used in patients who are unable to empty their bladder voluntarily or require temporary urinary catheterization.

The urine bag consists of a plastic bag with a capacity ranging from 500 milliliters to several liters, depending on the specific application. The bag is typically transparent or partially transparent, allowing healthcare providers to monitor the urine output and check for any abnormalities.

The bag is equipped with an inlet port or connector where a urinary catheter is attached. The catheter is inserted into the bladder through the urethra or, in some cases, through a surgical opening called a stoma. The urine drains from the bladder through the catheter and into the bag.

To prevent urine from flowing back into the bladder, a one-way valve or anti-reflux mechanism is incorporated into the bag's design. This valve allows urine to flow into the bag while preventing it from returning to the catheter or bladder.

The bag is also equipped with a drainage outlet at the bottom, which is typically sealed with a twist valve or a clamp. This allows for easy emptying and disposal of the collected urine when necessary. The outlet may also have a sampling port for obtaining urine samples for laboratory analysis.

To secure the urine bag to the patient, it is often attached to the patient's leg using straps or adhesive strips. This helps to prevent the bag from pulling on the catheter and ensures stability and comfort for the patient.

Urine bags are available in various configurations to suit different patient needs, including bedside bags for use in bedridden patients and leg bags for more mobile individuals. They are disposable and should be changed regularly to maintain hygiene and prevent infection.

Overall, a urine bag is a vital medical device that provides a convenient and sanitary means of collecting and managing urine output in patients who require urinary drainage.