Parts of a G Tube – Labeled Feeding Tube and Button

All 10 parts on the diagram

Show the list

Standard tube 8

Balloon A small bag filled with water. It keeps the tube from sliding out.
Tube The long shaft of the device. It passes through the body wall into the stomach.
Y-port The forked outer end: one opening for feeds, one for medicines.
Clamp A clip on the tube. It pinches the tube shut.
External disc A soft disc on the tube. It rests against the skin.
Tip The open end of the tube. It rests inside the stomach.
Balloon port A side opening with a valve. It leads only to the balloon.
Cap A plug on a strap. It closes an opening of the Y-port.

Button 2

Button A low-profile tube that sits flat against the skin.
Extension set A length of tubing that plugs into the button for a feed.

How this list was compiled: Every name checked on 2026-10-01 and kept only where two independent sources use it. (1) MedlinePlus (U.S. National Library of Medicine), Gastrostomy feeding tube - bolus, https://medlineplus.gov/ency/patientinstructions/000165.htm . (2) Cincinnati Children's, G-Tube Care, https://www.cincinnatichildrens.org/health/g/g-tube-care . (3) Great Ormond Street Hospital, Gastrostomy, https://www.gosh.nhs.uk/conditions-and-treatments/procedures-and-treatments/gastrostomy/ . (4) Wikipedia, text only: Feeding tube, https://en.wikipedia.org/wiki/Feeding_tube . (5) The Oley Foundation, Tube Feeding Troubleshooting Guide, read as text, https://archive.org/details/manualzilla-id-5825582 . (6) A community care agency's clinical policy, Percutaneous Enteral Feeding Tube Care, read as text, https://archive.org/details/manualzilla-id-6029236 . (7) AboutKidsHealth (The Hospital for Sick Children), a page on caring for a gastrostomy tube, https://www.aboutkidshealth.ca/Article?contentid=2536&language=English . (8) UPMC Children's Hospital of Pittsburgh, Gastrostomy, https://www.chp.edu/our-services/transplant/intestine/education/patient-procedures/gastrostomy . Balloon is in 2, 3, 4, 5 and 6; balloon port in 2 and 6; the outside disc in 2 (disc), 5 (external disc), 6 (retention disc or bumper) and 8 (bumper); clamp in 1, 5 and 7; the forked end in 6 (Y-port) and 7 (Y-adaptor), with 2 naming its medication port; cap in 3 and 5; tip in 4, 6 and 8; button in 1, 2, 3, 5 and 6; extension set in 1 and 2. Licence: own work

The drawing: Drawn for this site on 2026-10-01 from plain geometry; no maker's device, no body, nothing traced. Licence: own work

How it works

The parts of a G tube, a gastrostomy feeding tube, in two drawings: a standard balloon tube and a low-profile button. Names only: nothing here is medical advice, and no body is drawn.

Read the full guide

A standard tube

Outside the body the tube ends in a Y-port, a fork with two openings that a cap can close. A clamp on the tube can pinch it shut. A side arm, the balloon port, leads only to the balloon. An external disc on the tube rests against the skin. Inside the stomach are the balloon, which keeps the tube from sliding out, and the open tip.

A button

A button is a low-profile tube that sits flat against the skin. It has a stem and a balloon like the standard tube, drawn faintly here. An extension set, a length of tubing with its own clamp, plugs into the button.

This page names parts only. It is not medical advice.
The outside disc goes by several names: disc, bumper, bolster. The quiz takes them all.

Questions and answers

What are the parts of a G tube?

A standard balloon G tube has a Y-port with a cap, a clamp, a balloon port, the tube itself and an external disc at the skin. Inside the stomach it has a balloon and an open tip.

What is a G tube button?

A low-profile gastrostomy tube, also called a skin-level device. It sits flat against the skin and does not end in a long tube; an extension set is attached to it.

What holds a G tube in place?

On the inside, a balloon filled with water, or on other tubes a soft bumper that is wider than the opening. On the outside, a disc or bumper rests against the skin.

What is the balloon port on a G tube?

A side opening with a valve, separate from the openings of the Y-port. It leads only to the balloon, and the water that fills the balloon goes through it.