A Penrose drain is a soft, flexible rubber tube used as a surgical drain, to prevent the buildup of fluid in a surgical site.
[1] See photo of a Penrose drain & its packaging in the following external link: [1] A Penrose drain removes fluid from a wound area.
Frequently it is put in place by a surgeon after a procedure is complete to prevent the area from accumulating fluid, such as blood, which could serve as a medium for bacteria to grow in.
In podiatry, a Penrose drain is often used as a tourniquet during a hallux nail avulsion procedure or ingrown toenail extraction.
It can also be used to drain cerebrospinal fluid to treat a hydrocephalus patient.